Prototype is at it's heart - nothing more than a mish mash of different tried and tested gameplay and story elements. The free roaming owes a lot to GTA, the gameplay and powers are a lot like what you'll get in Devil May Cry and its ilk and the story is pretty much Resident Evil. While not having an original idea in its pretty little head and not being overly pretty... the game is still great.
Alex Mercer is a - sigh - amensiac who wakes up after being dead. He has to piece together his life and work out what's going on with the infection of Manhattan by a virus and yadda yadda yadda. It's not very original but who cares? YOU GET TO TOSS TANKS AROUND. Literally. You can pick up tanks, cars, helicopters.
The story really isn't very much to write home about - government conspiracy, supersoldiers resulting in zombies and that kind of thing. That's irrelevant - although, as a gameplay dynamic you can run around the city and "absorb" people to uncover the backstory of the game. This absorption can also be used to gain and improve skills and infiltrate enemy bases. It's actually a pretty nifty dynamic. Although, the AI in the game is so AWFUL that you can get away with just dropping 100m from a rooftop dressed as a soldier in front of another soldier and he'll high five you instead of shooting you in the FACE.
Not that point blank machine gun fire would do much becuase it's worth noticing even at the start of the game - you're RIDICULOUSLY powerful. Insanely super powerful and that is why this game rocks. On normal difficulty you are as a GOD. Once you kick in your power ups, you can shrug off artillery shells - small arms fire does noticing. You can heal by chowing down on unsuspecting people in most situations. Really only a pack of Hunters will poses a threat. You can hijack tanks and helicopters, fly (kinda), use the weapons of the soldiers and use a variety of abilities - whip, claws, GIANT SWORD ARM and enhanced strength. Plenty of moves to use.
Beyond the usual storyline missions there are GTAesque challenges that... don't really do much, they're just there for extra playtime. Running along the roof, absorbing people and good old fashioned murder. Not to mention you can just go and break into military bases or tear apart the hives.
The game is to be played purely for fun. There is no deep meaning. The game tries to inject some sense of an epic storyline with the "Web of intrigue" backstory mechanic but that's not really that important. Not are the mini-games - this game is about running around and smashing stuff in a number of awesome ways. It doesn't matter that the plot is a big cliche or that the voice acting is Resident Evil level... it's all just a bit of a laugh.
