In short, they took Prototype, broke it down, built it back up and turned it into something far more epic and bad ass
A lot of people turned a blind eye to Prototype one because of it's ongoing war with Infamous; but I honestly can't pick between them. On the one hand SuckerPunch is one of my favorite gaming companies because they gave me the Sly Cooper trilogy and then came out with Infamous and Infamous 2; which were both amazing games. On the other hand Prototype and Prototype 2 are far more violent and you basically hold the power of God in the palm of your hands; but some aspects of one game are better than the other but that is besides the point.
Prototype 2 delivered and lived up to the hype that was expected of it; or at least to me it did; I had taken the liberty of pre-ordering it and going to go pick it up upon the early morning opening of Gamestop that's how excited I was for it; and upon playing it, I was highly satisfied. I spent a total 12 hours playing the game and completed all of the core missions and a majority of the side missions within that time frame and then with the Radiant addition that can give you a total 3 or 5 more hours of gameplay and even once you beat the game, it's still fun to run around and just kill people for fun.
Sgt James Heller is an amazing, awesome, rough, tough and epic bad ass new character to take the place of Alex Mercer. Don't get me wrong Mercer was great but Heller grows on you much more than he does; Mercer was typically quite and bent on just one thing and didn't really give you much to like besides his powers and ruthlessness. Heller however is funny, has a total dirty mouth, sick sense of humor, and a strong sense of ruthlessness and brutality that greatly would make you think he's related to Kratos from God of War.
Overall the game is epic and I can honestly say...I sure do hope Radical tops themselves once again, if they decide to create Prototype 3!