The first-person shooter - and especially the "futuristic" first-person shooter - has been done, over and over, with little to no changes in gameplay, since almost the beginning of gaming itself. With that said, games like Haze occasionally try to mix things up a little, and while the idea is good, the execution ends up dragging it down a lot.
The underlying plot of the game, both single-player and multiplayer, is that, in the future, a company/organization called Mantel uses a drug called Nectar to produce a generation of drugged-up super soldiers to fight for them in the third world. Multiplayer battles consist of skirmishes between Mantel troopers and rebels, while in singleplayer you start as a trooper and switch sides later on.
The two sides have the same basic first-person gameplay, with some key abilities that are different. Mantel troopers inject themselves with Nectar, which enhances their perception (scopes can zoom in farther, enemies are rendered as glowing objects) and strength (soldiers move faster, hit harder, and regenerate health) as well as providing a hallucinogenic "high". There is a limited supply of Nectar that each soldier has, but it regenerates over time; the supply is counted in "shots" or "injections". Holding the L2 button down injects Nectar into your bloodstream, represented by a gauge. Release the button too soon, and you won't feel the effects of it for long. If you hold it down for too long, though, you can overdose, which renders you unable to tell between friend and foe. In many cases, when you are overdosed, you are unable to control yourself even to the point of randomly firing weapons or arming grenades (which you must shake the controller to throw away before it detonates). If you run out of Nectar, you are highly vulnerable; for this reason, you can usually siphon Nectar off of one of your teammates, if they have enough.
On the other side, the rebels are as weak in combat as a Mantel trooper without his nectar. They make up for this with various ingenious techniques. Some rebel weapons are coated with Nectar, specifically knives and grenades that are made from Nectar-packs taken from dead troopers. Both of these weapons can cause Nectar overloads in enemies, causing the aforementioned self-damaging effects. Playing off of Nectar's effect of making dead bodies "invisible" (bodies fade almost instantly when playing as a trooper, but remain for a long time when playing as a rebel), rebel soldiers can "play dead" when hit, and then "revive" after the troopers have left. Rebels can also do various mechanical improvisations, such as taking ammo from dropped weapons and converting it to ammo for the weapon they are currently using, as well as turning grenades into proximity mines. Finally, they're generally faster and more agile than their trooper counterparts, capable of dodging and in some cases stealing an enemy's weapon.
The single-player storyline is laughable, for the most part, with some interesting parts. You play as Shane Carpenter, wide-eyed idealist youth, who joins Mantel to make a difference and stop the unspecified mass murders and ethnic cleansings that the rebels are carrying out. The story starts on a carrier, where Carpenter meets his teammates - gung-ho, drug-fueled murderers in the finest traditions of sci-fi and war movies everywhere. Only, the difference here is that it makes sense - it's plain to see that Nectar screws with your mind just by the effects that show up when you use it in-game; the blurring, the sudden shifts of motion, and so on. Carpenter's injection system malfunctions several times, which (a) leaves the player unable to use Nectar's beneficial effects, and (b) causes Carpenter to see things that his fellow troopers don't see; a dying comrade, screams of pain, massive piles of bodies, and so on. Carpenter questions his mission more and more, eventually leading to his switch to the rebel side midway through the game. Most of the story is ham-handed dialogue, though there are some good atmospheric moments; walking through one burnt-down village, or trying to find your way through a swamp, for example. These moments tend to only use dialogue as background noise - the heavy-handed boasting of the Mantel troopers contrasts against the quiet of the jungle's ambient noises. The use of camera in cutscenes is interesting, but not really new; the view is always from Carpenter's first-person perspective, though in some scenes his visor will slide away so that the HUD doesn't block your view. In most cutscenes, you can look around but not move, lending at least some feeling of interactivity to the scenes.
As a whole, the gameplay - as mentioned - tries some interesting things, but ultimately falls short. A lot of it makes sense as a Mantel trooper - the poor control, for example, or the lack of solid feeling to movement and aiming - but when you're a rebel and you're supposed to be free of the hallucinatory drug, it's just bad. The guns are the most generic first-person guns ever - a pistol, an assault rifle, a shotgun, a sniper rifle, a chaingun, a flamethrower, and a rocket launcher. None of them handle well, and none of them are particularly fun or interesting, either. Grenades are pretty much worthless, and even in single player I've never managed to kill a person with one even when it exploded right underneath him. The vehicles handle incredibly poorly, often flipping with little to no provocation. On that note, your AI buddies all have roughly the same abilities as yourself, but if they die they are gone forever, and finding new allies is incredibly rare. With that said, most of the times I had allies die (counting times I reloaded afterwards) was in vehicle crashes, when I'd take too much of an angle, my buggy would flip, and my gunner would die. Other than that, the AI soldiers are reasonably helpful, though the troopers and their Nectar injections are much tougher and more helpful than the rebel allies, who lack both the strength of the troopers and the ingenuity of the player and are left with pretty much nothing.
The graphics are nice in some ways and terrible in others. For example, they load slowly, leading to that awkward phase where you watch a person's resolution increase in front of you. In other places, animation is jerky, or edges are jagged, or some other flaw exists that prevents the on-the-surface good graphics from actually being good. Furthermore, the designs are both silly and generic, especially the Mantel vehicles and their bright yellow glass. The voice acting is generic, too; not bad, but by no means actually good, and the ridiculousness of the lines makes up for whatever points good voice acting might have gained.
This game has some good ideas, but the underlying genre of futuristic first-person shooter and the incredibly poor execution of graphics and gameplay render this game unbearable. For PS3 shooters, Resistance was better; for shooters in general, pretty much anything is better. This game doesn't deserve anything higher than a 4/10.