I LOVED [PROTOTYPE]. It was some of the best fun i've had in a while with a game. Just a lot of freedom of movement with a very free-style type of combat providing a quick change wheel for all the different abilities. I guess i'm so used to there being boundries on these action types like DMC, NG and even Bayonetta doesn't compare to the amount of control and freedom given on Prototype. You can climb any building at any time. No invisible walls except for the very edges of the map. Even then, it's not really an invisible way per say, the game just makes Alex travel back towards the island if you manage to travel far enough. If you travel too far on a bridge, i believe you get bombed! To me, that stuff is just cool. Its not lazy ass, lame invisible wall crap. The list goes on.
There are a tremendous amount of different ways to go about combat in general. Any weapon can be picked up and fired until it runs out of ammo. Which you wont miss it too much because they are litterally found everywhere and there is a decent variety of pick-ups. If nothing else, you can always pick up vehicles and throw them like....half a mile! And its New York, so yeah...there are a lot of cars. The weapons and vehicles are not so much better than your base abilities that you feel the need for them but they do provide enough advantage and edge for you to use them as they become available. An absolute perfect balance on that IMO which makes for a LOT of variety in game play.
The stealth mechanics are a nice addition to the game. It's not terribly fleshed out or comparable to what you would find in other games that do it much better but it's not supposed to be the main foccus of the game, just another tool you can use to make some of your missions a tad bit easier and a bit more varied.
People are knocking the story and plot pretty hard but i thought it did it's job well enough. I was genuinely intrigued when i discovered the "truth" about Alex Mercer. That whole Web of Intrigue really helped the story i thought. It was a lot of fun consuming all of those targets and piecing together more of the story each time. Generally games have useless, lame collectables that do absolutely nothing. Web of intrigue targets provided a Picture/video/vocals for each one that was either relevant to the story or at least entertaining on some level and there's like more than a 100!
The voice acting i felt was a very strong point for this game. It's entertaining to hear all the mililtary radio transmitions throughout the game while they are chasing you because you just blew up a military base.
I think i know why people are complaining about a lack of variety in enemies to fight. There are two distinct classes of opponents here which are military and infected. There are 7 or 8 different types of infected, most of which dont really get a lot of spotlight or attention thus i'm thinking they just kind of dissappear in all the chaos. The military get about the same level of variety. Generally speaking, you're isolated to one group or the other so thats probably why people dont notice the variety of both as much. As you progress through the game, the two tend to mix more often. You can even use run tactics to brush pursuers off on the opposing team because it's always a free-for-all between Alex, the military and the infected.
The only honest gripe i have with this game is the control can be a little to liberal at times and this will especially come to light if you try to complete some of those challenges. Particularly timed events with races and such on rooftops, its a pain in the ass if you accidentally air dash just barely off target because you end up 30ft out of the way forcing you to start over the event.