I quite enjoyed the first Prototype game -- there was barely any structure to the game, but it served as a decent enough playground. The star of the show was really the upgradeable powers, and the overwhelming feeling 'I AM A MEGA GOD' feeling that came with those powers. I haven't had the time to play Prototype 2 yet, but I'm really keen to hear what you guys thought so far...
The vibe I'm getting so far, is that it's superior when compared to the original. Still as mindless as the original, but featuring enough interesting core mechanics to keep your interest sustained.
It's so stupid, but the game's trailer, which featured the warblings of Johnny Cash and took itself painfully seriously, really put me off to be honest. I think the one thing that could really convince me to invest time in the game would be a set of fun mechanics and that seems to be what the game is in possession of.
So, yeah -- folks that have played the game -- convince me!