A Mouthwatering, Violent, Vulgar, and Amazing Ride.
Gameplay: It's a rail shoot, but it's not. It's essentially an adventure/rail-shooter with some puzzles. I can honestly tell you it doesn't get boring. Well, for me it didn't.
Graphics: Beautiful cel-shading. I usually hate cel-shading. It's quite disgusting depending on how developers utilize it. In Killer7's case, it's beautiful. It goes along with the entire premise and story. The characters look brutally beautiful in the cut scenes. They ooze depth and meaning. Let's just put it this way, this game is visually mouthwatering.
Sound: Amazing voice acting. Immaculate soundtrack. Both of these features add to the already amazing story line, and take you deeper into the game.
Overall: This is a game meant for people who appreciate good stories, and can handle difficult challenges. Definitely not for the average gamer, or person in general. I can honestly tell you that you need to make your own opinion and not follow this review.