Killer7 is a really novel action/puzzle game from the brain of legendary gaming icon Suda51. This is the same person that brought us the likes of No More Heroes and Lollipop chainsaw, just to give you an idea of the sort of game we have here: it is pretty bonkers.
But I wouldn't be put off by the quirks, this is a really fun game. You play through the game as a number of different characters, each with their own attributes that bring something different to the game. You can swap characters throughout the game, but you may only change to characters that the designers allow you to. The main game is sort of on-rails in that you hold down a button to run forwards and another button will spin you around on the spot to run in the opposite direction. Your character will run along a fixed path but there are occasional junctions that allow you to choose your route. At first this may seem a bit inhibiting, but it becomes a very satisfying way to move around the game world. At any point, you can hold down a trigger button to go into first person mode, where you can shoot any surrounding enemies. The enemies are invisible until you go into first person mode and press a 'scan' button. You can then shoot at any enemies, with extra points and quicker deaths for hitting their sweet spots which are located on their bodies.
There is so much that could be said about this game that it would simply be impossible to fit in an entire review and probably even harder to explain, you just have to play the game for yourself. I can only really liken the game to some kind of strange dream or after-life like experience such is the nature of the cell-shaded graphics, the strangeness of the characters and the craziness of the plot. It truly is a surreal experience.
With about 8-10 hours of storyline, there is plenty to get through and you will probably want to play through it all again afterwards. My only really complaint is that there are periods where I found myself left wondering what to do next, and sometimes dying and having to re-do the last section can be a little frustrating, but this are relatively minor complaints really, otherwise this is a highly recommended game.