After the tutorial you will have to do missions to progress in the story line but there are also a some sort of mini games you can do to gather EP (Evolution points) with these points you can buy upgrades for Alex. EP points are very easy to gather you don't have to do missions or minigames to get them at all you can just roam the city and cause total destruction/mayham to New York to gather them by for example: killing infected, killing blackwatch soldiers, destroying heli's, tanks, Blackwatch bases or Infected hives.
The game overall plays pretty good but the tutorial can be a but quick or a bit confusing and the controles can be to at first but when you have mastered it the game plays like a charm. The graphics are a whole different story for a next-gen game this doesn't really look all that next-gen the characters faces all look like they were made out of clay or something. (maybe a bit exagerated but it's really not that good.)
The music is forgettable there is some in it but not worth mentioning and the voice acting isn't all that great either, there are some things you can unlock when you finish the game but those aren't really that great at all.
(you could allways go for the trophy's or achievements)
Overall the game is very fun to play but you can finish it in under 20 hours, just fooling around causing mayham with ultimate powers is fun, but it can become a bit stale after sometime for some people.
The verdict
Graphics: 6
Sound: 6,5
Gameplay: 9
Replay value: 7,5
Overall: 7,5
Rent or buy: I'd say rent it first and see if you like it or not if you do it's a definite buy
Available on: Xbox360, PS3 and PC