It feels like just that, a prototype...

Prototype is a game that feels like it released before it should have, its unpolished, it has terrible voice acting and during certain points is just a chore to play; it feels like a prototype to a bigger and better game. Now normally I don't put a major emphasis on graphics but in Prototype's case I feel I need to make an exception: its not that the visuals are bad (when the action gets going and there are perhaps hundreds of different NPCs on screen, including civilians, foot soldiers, tanks, APCs, helicopters and the infected you will be impressed with the fluidity of it all as the frame rate rarely dips and the camera keep up with everything that you are doing) its that they are bland and boring and basic.
Buildings repeat over and over all with the same windows and rooftops, in fact, aside from a few obvious landmarks (the Empire State Building, Time's Square) I'd be hard pressed to tell you it looked anything like Manhattan it is ridiculously generic...but hey, at least its big (well actually its' size works against it; because everything looks the same its not that fun to travel the city just to enjoy the scenery, like most open-world games.) On the plus side Alex is quiet well animated and some of the powers look absolutely devastating.
The voice acting in the game is just horrendous and the main reason the story in cut scenes in nearly unbearable (which is disappointing, because the Web of Intrigue is quiet interesting) . Its annoying to watch a cinematic where the actors sound like they are just reading straight off the script in a rehearsal: no emotion and no pausing for proper dramatic effect or even punctuation, in one scene no one stops at the end of a sentence they just keep going...and its a long cut scene. Its also hard to care for any of the characters when the voice acting is this bad, not to mention contradictory; for what ever reason at random points during the game the characters (Alex especially) would say things that were completely out of character, like Alex, suddenly questioning his murderous actions...AS HE'S RUNNING OVER PEOPLE WITH A TANK!
Finally, at odd times the challenge just skyrockets, and its not that it becomes more difficult, just frustrating. You suddenly will have your powers taken away (for really stupid reasons too, the first time comes right after a boss fight where you seemingly win the fight only to discover, "no sorry, but Alex was the one who got beat and the boss is fine"; you'll know when it happens, and its headshakingly stupid) and after losing you're powers the army and the infected send seemingly EVERYTHING after you with no good way to escape as they can apparently see through walls.
I've been harsh on Prototype so far but ultamitely its not a terrible game, it just isn't all that great either. There will be people who enjoy the voilence and the little else that the game gives you and if you are that kind of "pass the controller around" player who normally has others watching while you play than this is a good game to get (or rent, I'd say rent first) as it may be ugly and have terrible storytelling (though an intriguing back story) but it is chaotic and violent and it just never stops.