If you want to dislike Edge of Tomorrow, keep reminding yourself that it's Tom Cruise in Groundhog Day meets Independence Day--the world has been invaded by aliens, but Major-busted-to-Private Cage is repeating the same bloody slaughterhouse day over and over and over again.  However, it is a lot better than that.  Cruise (who appeared in Minority Report, which on examination proves not to be a time travel movie) gives us a respectable turn in the role of Cage, the action is relentless, the relationships compelling, and the story just twisted enough.

The film also provides a pseudo-rational explanation for the time travel element (making it more akin to 12:01 than to Groundhog Day).  In this case, the aliens have a telepathic hive mind with a central core and a tiered control network--the core makes decisions, the blues form the communication network and control the blacks, which are the drones.  If a blue is killed, the core, in a reflex action, resets the world to the previous day and replays every action through that point so that the blue will not be killed.  However, in a biologically improbable accident, if a human dies drenched in blue blood as he kills a blue, he gets tied into that network such that his death will return him to the previous day just as would the death of a blue.  That happens to Cage, who keeps going back to a moment when he awakens in handcuffs (busted to private for desertion when he refused an order into combat) and quickly realizes that he knows what is going to happen and no one else does.

He learns that if he makes a mistake, he dies and starts over, so he can gradually form the day into what he wants it to be.  He thinks he's going crazy, but he saves the life of Rita, also known as "The Angel of Verdun" because with no advance training other than an introduction to their low-level cyberpunk combat suit she single-handedly killed over a hundred aliens on her first day on the field.  When he explains to her that he knows what is happening because he already lived through the day, she tells him to find her when he awakens.  When Rita asks him who told her he could speak to her, he tells her that she did tomorrow on the beach, and she quickly takes him and introduces him to the physicist who is the only other person who believes him--and Rita believes him because that's how she got through Verdun, repeating the day and learning not to make each mistake, until on some trip she did not die and the medics saved her, giving her several pints of blood and erasing her connection to the core.  However, she intends to train him and go with him, to find and destroy the core.

The fact that history is repeating but one person remembers it makes it seem as if it is a sawtooth snap, but it's more complicated than that because the future end keeps shifting.  It appears to be the sort of time travel we see in the Butterfly Effect franchise, and more recently in About Time and X-Men:  Days of Future Past, in which the time traveler's consciousness and memories replace those of his former self, but without the ability to return to the future other than by living through the events again.  We thus have a time traveler who uses his knowledge of the future to prevent the future on which that knowledge is based--repeated infinity loop material.

The end at first looked like it was going to pull a twist out of Triangle, as having finally located and killed the core Cage awakens earlier in the day--before his arrest and court martial.  However, there is a reasonable explanation for this, although it is weaker than the explanation for the other.  It is also peculiar that when they destroy the core, the destruction also works back a day, which sets up its own temporal disaster--but it is evident that we will have to do a more complete analysis when we can study the film in more detail.

If you are seeking this film on the shelves of your video store, don't look for the title; it's in small letters at the bottom.  Instead, look for the large words

LIVE
DIE
REPEAT

Major William Cage, from the United States Army public relations department, makes the mistake of suggesting to British General Brigham, Commander of the United Defense Force, to whom he has been assigned, that sending him, Cage, into a combat situation to provide coverage for it that will improve the general's public image would be a mistake; Cage is in public relations to keep him away from combat, and if forced into combat he will use his significant public relations skills to make the general look bad.  He awakens from being tasered in handcuffs on a stack of duffelbags at Forward Operating Base Heathrow, stripped of rank and under the command of a Sergeant Farell, whose orders include that every fact Cage is likely to state is actually a lie and he is a deserter to be prepared for combat at the front.  He is assigned to J Squad, a company of similar misfits being ridden hard by this tough sergeant, and his efforts to get out of the situation do not succeed.  At dawn he is aboard a drop ship in a suit of light power armor he does not know how to operate.  The ship is hit less than a minute from its drop point, everyone drops, and he is in combat.  It is a slaughterhouse; the enemy is not at all surprised, and tears through them very quickly.  They have the look of black armored squids, move at highway speeds, leap with deadly accuracy, and usually kill with a single hit.

Cage manages to figure out how to activate the suit weapons about the time his squad is massacred, and exhausts the ammo very quickly.  He then is confronted with a squid that has a bluish color, closing swiftly.  He sees a dropped Claymore, clearly marked "This side toward enemy", holds it over himself, and activates it as the blue attacks.  Bathed in the blood of the blue, he dies.

Then he finds himself awakening in handcuffs on that stack of duffelbags at Forward Operating Base Heathrow, Sergeant Farell making the same speech he already heard, being taken to J Squad, and the only one who feels like this has all happened before.  It is only getting started, though.  He will repeatedly die in the battle and awaken on those duffelbags with that sergeant ordering him to his feet.

It is not possible to count the number of times this happens, because it is evident that the film omits both long segments of repeated days and entire days--that is, sometimes we see that Cage knows what is about to happen because he has been through this part before, but we did not see him do so.  The film plays somewhat fair--it is clear that sometimes he reaches the point at which he does not know what is going to happen next, and then they play it forward until he dies and resume at a point which we can extrapolate is what he chose to do instead.  Each time he revises his actions, attempting to live a bit longer and get a bit closer to defeating the enemy.  He has a couple of allies and a number of setbacks, and the film does have a "happy ending" so ultimately he succeeds--not the way we expect, perhaps, but quite completely.

The mechanism for the time travel is important to the plot.

We described the events that put Major-cum-Private William Cage into his time loop; the film offers an explanation for it, largely through the past experience of Sergeant Rita Rose Vratowski and the theories of Doctor Carter, particle physicist and advanced microbiologist reduced to glorified machinist because of resistance to those theories.

The invading enemy, which for some unexplained reason is called the "mimics", is actually a single telepathic organism of sorts.  The black squids, called drones, are expendable appendages that do all the work.  The blues, dubbed Alphas, are akin to the central nervous system, connecting the blacks to the brain, the core, called the Omega.  The Omega directs the battle through the Alphas by a telepathic link of sorts.  More significantly, if an Alpha is killed at any time the Omega causes the day to be reset, very like returning a video game to the last save point.  They say that the Omega has this ability, but it seems it has no control over this ability--it can neither reset the day without the death of an Alpha nor decide not to reset the day if an Alpha is killed, it simply resets the day automatically upon the death of an Alpha.

It can, however, sacrifice an Alpha in order to reset the day.  Further, it alone remembers the events from the previous version of the day, and from every other previous version of the day, and so can make changes in its moves so as to avoid the event which caused the reset or made the reset desirable.  Thus it is never surprised by the enemy, because if it is surprised by the enemy it simply sacrifices a blue and resets the day so it can change its field position to anticipate the surprise.  As Rita says, "An enemy that knows the future can't lose."

Fortunately, in an extremely improbable quirk of biology, there is some kind of affinity between human physiology and mimic physiology:  if an Alpha and a human die together such that the human is drenched in the blood of the Alpha, the human takes control of the Omega's reset ability.  The human has no more control over it than the Omega, but as long as the condition holds the day will reset whenever that human dies, but (apparently) not when an Alpha dies.

This retroactively explains how Rita Vratowski, with no more than cursory training in the power armor, became The Angel of Verdun and the military's poster girl, killing hundreds of mimics on her "first day" in the field:  every time she was killed, the day would restart and she would remember how she was killed and avoid it the next time.  Then something happened--we are told what, and will get to that--and she lost the connection.  She comes to the battlefield at the beginning of the movie expecting to die, and there, on what appears to be his fourth time through, she discovers that he now has the ability she had, because on his first time through that Operation Downfall attack he killed the Alpha and died drenched in its blood.  She tells him to come find her when he awakens, and lets them both die.

All of this is reminiscent, of course, of Groundhog Day and 12:01, two films in which the main character is the only one who experiences the day repeating and remembers events.  12:01 explains itself, in that a botched scientific experiment one night resets all events to the previous night, exactly twenty-four hours earlier, and the repetition can only be ended when the main character determines why this is happening and prevents it.  In that sense, this is closer to Groundhog Day--we are returning to a reset point, the moment the character awakened the day before killing the blue.

It is also significant that with each new day he does not kill the blue; that he did it once seems adequate to create the condition.  That is our next problem.

The mechanism that caused the time travel was connected to the fact that a human died soaked in the blood of a dying Alpha alien, such that the human had alpha blood giving him a connection to the Omega and control, such as it is, over the time travel reset power.  This is an interesting pseudo-rational explanation, but it does not withstand scrutiny.  There is an inherent inconsistency in it.

First, attend to the fact that the link is broken for both Rita and Cage the moment they receive a blood transfusion because of blood loss.  That is significant, because it indicates that the connection is based on the fact that their blood contained something from the Alpha blood that caused the link.

Now consider that whenever either of them returned to the beginning of the day, all injuries were erased; they were fully healed.  Further, everyone else was returned to that moment alive and in whatever condition they were then.  That includes the Alpha mimic that had been killed, whose blood infected the human involved.  In other words, that death never happened; it is merely a memory of events that have otherwise been erased.  Therefore Cage's blood was never infected.

It is also important to recognize that Cage does not die bathed in the blood of an Alpha the second time through, nor the third, nor again in any of the repetitions we observe.  It does not appear necessary for him to become reinfected.  The first infection is sufficient to keep him infected thereafter until he loses enough blood and is tranfused with clean blood in sufficient quantity to dilute the Alpha factor below its effective level.

We must believe that somehow the alien blood itself must travel back in time and infect the affected human that morning.  It is the only explanation that makes sense of the way events occur in the film:  whatever it is that links Cage to the Omega travels back to the reset point whenever Cage is killed, not to where it was then but to where Cage was then.  All of Cage's memories travel with it.  If we accept that explanation, it explains why Cage is still infected on the many days on which he does not kill an Alpha.  If it is in the blood when he dies, it travels back to the reset point and infects his blood before he awakens.

It does not explain why losing a large quantity of blood and having it replaced by clean blood removes the infection.  That remains something of a problem.  It appears that he can die from "bleeding out", which means he has lost so much blood that he is no longer alive, and still have enough of the Alpha factor in his blood to retain the connection and reset the day.  However, if before he has lost that much blood he is given clean blood he no longer has enough of the Alpha factor to do this.  The logic of it escapes scrutiny.  If he loses some blood and has it replaced by clean blood, he still has more of the Alpha factor blood in his body than he does if he loses more blood and dies without having it replaced.  Granted, the story needed some way to break the connection.  If we allow it all its assumptions to this point, this way does not seem to fit quite right.  That is, it must be that Cage would not be able to reset the day if he lost enough blood, such as by bleeding out, before he died, because if he still has enough Alpha blood to reset the day if he dies of blood loss then he still has enough Alpha blood to reset the day if he does not die of blood loss but is saved by an infusion of clean blood.

We have made reference to the reset point.  That is our next complication.

Once Cage is infected, whenever he dies the infection itself travels back through time to what we called the "reset point"; previously we commented that it was similar to the last save point in a game.  There is definitely some confusion about this, though.  We will need to look at a timeline.

Cage is talking to General Brigham the day before Operation Downfall; he awoke on the helicopter in daylight in London, but since he did not ride a helicopter across the Atlantic he must have been awake somewhere in (or near, such as on an aircraft carrier) England not long before.  We see the face of Big Ben as it strikes seven in the morning.  After his arrival and meeting with the general, he is tasered and handcuffed, his uniform is stripped of rank, and he is delivered, unconscious, to Heathrow, which we take to be at least near the airport of that name, which means the outskirts of London.  It is still daylight, and still the day before the invasion; he has enough daylight that on later runs he manages to escape from training, persuade Rita to train him, get in a significant amount of training time, and be with the squad to suit up the next day.  They leave Heathrow in daylight, and drop on the beach sometime that morning.  Note that they are attacking to the west, so morning reaches the battlefield before it reaches London, by a relatively short time.

When Rita explains what is happening, she says that the Omega "resets the day".  What, though, does that mean?

It does not mean that the day resets to either daybreak or sunset.  Daybreak of this day would find Cage in the barracks preparing for the assault, and Daybreak yesterday is before his meeting with the General; meanwhile, sunset yesterday is several hours after he awakened on the duffels.  Nor is it midnight.

Nor can we suppose that it resets to the last time Cage awoke.  It is inconceivable that the troops were permitted to stay awake overnight the night before the battle.  Although we do not see it, we must assume that Cage slept in that bunk he claims, and therefore that the last time he awoke was this morning.  In the final reset, when he travels back to the helicopter, he has also skipped the time when he awoke on the duffels.  Just about any notion we would have of the "beginning" of the day does not fit with the reset point.

It is not impossible that the reset point is the most recent noon, the moment the sun passes directly overhead, probably wherever the Omega is hidden.  This is improbable, both because the Omega is hidden well out of sight of the sky and because it is far enough north that it is out of the tropics--the sun is never directly above it.  Certainly there is radiation from the sun, but not enough to penetrate to the Omega; certainly there is gravity, the tidal pull, but that of the moon is far greater and would disrupt any simple organic detection of the gravity of the sun.  It might be based on the information from the network of mimics on the surface, but given that they have at this point spread across most of Europe and parts of Asia and Africa, the sense of when "noon" comes would not be a very accurate one.

We then might suppose that the Omega sets time back twenty-four hours.  The improbability here is that Cage is almost certainly killed the first time less than twenty-four hours after his meeting with the general--morning assaults are done early, and troops were on the move before daylight, so Cage's wave was probably not as late as the start of business hours at the office.  There is also no particular reason for an alien organism to adapt a reflex action to our planetary rotation.  So perhaps it sets the clock back twenty hours, or eighteen hours thirteen minutes twenty-seven-point-four seconds, or some period which is connected to its own evolutionary roots.  It just happens that however long a backstep it makes moves Cage from the battlefield to the dufflebags.

The problem with this is that each time Cage lives a bit longer, and ultimately he lives many hours longer, yet his reset point never changes.  He does not go back the same amount of time, but back to the same moment.

That may be part of the peculiarity of the human/mimic connection.  Obviously Alphas are always infected, and obviously their reset points must change--that is, every Alpha has probably been killed at least once, resulting in a reset that enables it to avoid being killed at the same time and place, but then many of them have been killed again, whether hours or days or years later, and they must travel to a different, more recent, reset point.  Somehow when a human becomes the controlling connection, the reset point becomes fixed to a specific time and place some temporal distance prior to the death, and probably a moment at which they were unconscious (Rita said to Cage, "Find me when you wake up", so her experience also involved traveling back to a moment when she was unconscious).  Then as long as the infection remains the reset point is unchanged.  Again it is unexpected, but it at least is not completely inexplicable.

We have already noticed that whenever Cage (or Rita) returned to the reset point, all physical injury was erased.  Physically it is as if they never lived through that time; only their memories and the connection to the Omega remain from the previous iteration of history.

However, that seems not to be strictly true.

When Rita first meets Cage, she is supporting herself balanced on two hands parallel to the floor--an impressive feat.  Perhaps it was something she could do before she became a soldier; we do not know that.  What we do know is that she begins training Cage, who learns how to fight effectively.  Certainly part of that is mental, that he knows what to do; but that kind of memory is like trying to win a martial arts competition by reading a book about martial arts.  Anyone who has studied a martial art--or indeed, a musical instrument, or an athletic or acrobatic skill, or a complex craft like knitting, or even typing--has the experience of muscle memory, that your brain does not think through the movements but simply triggers your muscles to do that which they have done a thousand times before.  It is one thing for Cage and Rita to memorize what is going to happen and what they have to do to stay alive and get past the obstacles.  It is quite another for them to develop the physical skills and muscular strength and coordination to fight as they do.  If their bodies are reset to the start of that afternoon, then every day the training begins from nothing more than the memory that they did this yesterday but have no residual benefit from it.  That is, although every day Rita trains Cage, each day Cage has gained as much from the previous day's training as perhaps we did by watching it.  He remembers how the training is done, but his body never actually experienced it.

In fairness, the same mistake was made in Groundhog Day when Bill Murray's character learned to play the piano.  I can teach you how to play the piano in a single session, but if you want to learn to play the piano, you will have to invest many hours into practice--and not have those hours erased by time travel taking you back to who you were that morning.  Muscle memory, the development of strength and coordination, is part of the physical body as much as injuries and scars, and if the body is restored to its condition at the reset point, it loses all it obtained, both good and bad, since the last reset.

Perhaps we are supposed to believe that Rita was always that good and Cage only improved to the degree that he was able to anticipate events, but that is not the way it seems.  In any case, the daily training will always start with the version of Cage who argued with the general that morning, but that he knows what to expect.  It is not totally without benefit, but is something like a violinist being handed a complex sheet of music and being told to be ready to play it on the piano tomorrow.  He probably will know what it should sound like, and how a pianist would play it, but getting his fingers to do the job is an entirely different matter.

In About Time, Tim's Dad used his time travel ability for time to read.  If you find yourself in a loop of this sort, that is probably the best way to spend it.  Most things you might learn to do will involve training muscles which will be restored daily to their untrained state; only information acquired will remain with you.

There is a logic in the repetition which lulls us into believing that the system works; however, it breaks before the end.

The problem with most time travel stories--the problem that we saw in X-Men:  Days of Future Past--is that once a time traveler has altered the past he will not make the trip to alter the past, so the alterations will be undone.  The time traveler's duplicate does not know what he has to do, because he lived through a different history.  Here, though, the memories of all previous iterations of the time traveler are preserved in the present version, and so Cage knows what he has to do.  Yet this is flawed, and flawed twice.

In his first time through the day, he dies while killing an Alpha.  In the second iteration, he avoids the confrontation with the Alpha, as we previously noted, and so does not die at that moment.  Of course, things are very confused on that battlefield.  On his second trip he saves Rita, and then dies when she takes his battery and leaves him on the battlefield--it might be sooner, it might be later.  Eventually, though, he lives past the moment he made that first trip.  So Cage receives knowledge of what is going to happen on the battlefield up to the moment he dies with the Alpha, then replays the day, avoids the Alpha, and so lives past the moment from which he traveled back to his past self.  That means at that moment he did not send his memories back to his past self, which means that he, in the past, did not receive them.

Some will say this is not a problem, as long as eventually he receives those memories from his previous self, and he will at the moment he dies.  However, we then hit the problem with the penultimate.  We know that in his penultimate trip to the past, he and Rita exited from their visit with the general through the front door, were confronted by security, and she shot him in the head.  We then assume that everything through the visit with the general is replayed, and this time they exit through the parking garage and are escaping in a car.  This time Cage never makes the trip back--he is injured and captured, and the blood transfusion eliminates his connection to the Omega.  That means he does not take these memories back to himself, and he never receives any memories because there is now no version of history in which his memories actually are transmitted from the future.

Here we must assume that the film has accepted the dubious interpretation of Niven's Law, that once the past is changed it remains changed.  That is the only way that Cage can have those memories without having sent them from the future.

Yet there is still a significant problem with the time travel as we reach the end of the movie.

Eventually Cage loses the connection to the Omega, but not before he manages to establish its location.  He and Rita have one chance to destroy it; they enlist the J Squad misfits and steal a dropship.  Everyone dies.

However, Cage manages to get within striking range of the Omega, and as he is dying submerged in the water in which it is hidden he waves to the Alpha which has just skewered him, and shows that he is still holding all the pins from the grenades on the belt that has just fallen into the core.  As they explode, he succeeds in the mission.  It was a suicide mission, of course, but suicide missions are considered worth the cost if they succeed, and this one did.  Cage, the Alpha, and the Omega are all killed in the blast, which somehow goes beyond them to destroy the Louvre itself (somehow the grenades triggered the energy held in the Omega).  Blood and gore from the Omega floods the water, surrounding and clinging to Cage as he dies.

Of course, no one could know this because it had never happened before, but as Cage dies soaked in the blood of the Omega, he awakens earlier--on the helicopter headed into London for his meeting with the general.  As he lands he receives word that a huge power surge was detected in Paris shortly before, and the mimics have lost all ability to fight and are falling before the human assault.  Somehow the death of the Omega has worked backwards, restoring Cage to life at a new reset point about a day prior to their late night victory.

It certainly makes sense that if the creature resets time whenever one of its control units is destroyed, it would do so when its core was destroyed.  The problem is that doing so did not result in restoring the Omega--it is now dead, and dead a full day before it was killed.  So how was it supposed to work?  Assuming the process evolved to preserve the species, how does this reset do so?

There would of course be some things the Omega could not survive.  Most of them would kill everything anywhere near it, but that might not be a problem if it can reset time backwards one day.  It also appears that it keeps one of its precious Alphas near itself.  Perhaps the expectation is that in its death throes it would, through its own blood and gore, transfer its ability to the nearest Alpha, which would then grow into a replacement Omega in the beginning of the temporal reset.  The new Omega would then have the reset power.  However, in this situation it was not an Alpha but Cage who, being the nearest creature to the Omega capable of tapping the power, became the new Omega.  Thus as Cage dies, the system resets to the new reset point, and Cage is alive and in control of the power.

This means that Cage is now trapped in a considerably larger loop.  We have already seen that the moment of death is no longer connected to the reset time--that is, once the reset time is established it did not matter whether Cage lived twenty minutes or twenty days, his death would return him to the duffels on the tarmac.  Presumably now that Cage has the power in himself, whenever he dies he will return to the helicopter--whether in twenty minutes or twenty years.  Of course, the Omega is dead--but then, the Omega was dead a full day before Cage made the return trip to the helicopter.  The power now rests in Cage himself, it would seem.  He can die, but then he will have to live through it all again.

Of course, he knows how to prevent it--if he manages to lose enough blood and get a transfusion, he will lose the power.  On the other hand, he might well want to retain the power.  After all, whenever he dies, he gets to go back and live it all again from this moment forward.

The rest of us, of course, will cease ever to have existed at the moment he dies (as of course everyone did all those other times he died), but will immediately be replaced by whoever we were at that moment and also live it all again (without the knowledge that we have done this before).  Some will never reach aspirations because that moment will never come; some will be saved from disasters that will never happen.  All of us will be oblivious to it.  For Cage, at least, it is interesting futures.