You aren't playing this like you should.
While everyone is trying to be the next Halo, Killer7 does nothing any other game does. Classifying this game into a genre would hurt your head and make explaining the game to friends a pain, so here is practically what Killer 7 is.
Third person, action, advenutre, rail, puzzle, first person, surreal horror shooter.
The game utilizes all these and yet is still a fantastic game.
the game has you play as 7 different personalities, all of which with their own abilities and weapons. My personal favorite is Con Smith, who runs fast and has fast dual pistols.
The story is AMAZING, it's well written, confusing, and fantastic, it's on my lists of best stories ever told in a game, right up there with Penumbra and System Shock 2.
The only real flaw is the puzzles, which are boring and easy. But that doesn't really change anything, the game is still amazing.
Since you aren't playing this game, you should, and if you don't, you are dumb.