Prototype!
Most games start you off pretty wimpy, letting you upgrade or grow into new powers as you move along. In the final levels, you're playing a really fun character full of possibilities. But then it ends.
Prototype begins where these games end. You start the story cranked to 10, playing a massively powerful creature who can down a small army without much thought. Then the upgrades come and you turn the knob up to 15, becoming even more of a badass. And just when you think you've got all it can give you, in comes more upgrades. Prototype is what happens when you take GTA's city, mix in Assassin's Creed's gameplay, and add the visceral destruction of Rampage.
Unusual for a zombie story, it doesn't try to be horror or survival. You aren't or cleaning up after the infection or trying to prevent it from starting. You play an amnesia-stricken infected in search of the truth -- who he is, what he is, and what happened to New York City. You're put smack dab in the middle of a mostly pristine city and get to watch as the entire thing becomes more and more infected as you progress through the game.
Nearly every mission has you doing something new, keeping the gameplay surprisingly fresh all the way until the end. Sometimes you help the infected, sometimes you help the military. Usually you're fighting one or even both at the same time. When not on a mission you're able to roam the city, causing mayhem to your heart's content.
My only wish is that free roam was a bit more challenging—in GTA, the toughness of enemies slowly builds up until you can't take it anymore. Lacking this build-up, Prototype only has two levels of toughness: first the enemies become aware of you, then they call in a strike team. A pack of helicopters, strike teams are initially pretty hard but become very easy once you learn how to fight them. Eventually they devolve to the point where you call them on purpose, thinking "hey, free helicopter!".
Free roam aside, I'd recommend this game to anyone for the ever-changing and sometimes very challenging story. After spending a couple days trying to beat the ridiculously hard final boss, I finally finished the game this morning.
