Finishing this game made me some what sad, I really enjoyed the rooftop jumping once I got the hang of it, and all the disguising and hijacking/skyjacking military equipment was tons of fun. Flying around NYC in a Blackhawk, buzzing the tower (the Empire State Building), watching burning choppers crash to the ground, or pelting zombies and copperheads (huge ugly snake monsters) with death from above it was all enjoyable, and not difficult to master. Hijacking Tanks and APCs was another enjoyable part of the game, and sometimes a necessity to the completion of a mission(Good tip: if you are having trouble with a mission, try jacking some armor).
After some more plot twists mid-story line, your character gets some really cool upgrades like the armor suit, looks pretty bad ass when you morph your arms into some weapons, but as I said before its very Spawn-esque, but doesnt make the effect any less enjoyable. I skipped most of the extra events, side quests you can do to get extra EP (Evolution points) which can be spent to purchase new powers, or upgrade existing ones.
Over all this game gets a 4.5/5 on the Brawlking game scale. I would highly recommend this one if you like SciFi and RPGs.
Now on to Fallout 3 (I know, it's old, but I havent played it yet).