6. Obvious Hitman series.

A sandbox levels with a limitless ways to kill anyone. Stealth, fibre wire, crowling and hiding bodies, gun blazing through the scared crowd or making the traps - this game makes you feel like a serial killer. Lots of females, spectacular animations, bullet holes, wound animations and so on. New Hitman series is probably the best, Blood Money is a classic, Contracts is the most gothic and edgy one, and the Silent Assasin is almost impossible to stealth through, but pretty fun to play through with occasional gun blazing. First Hitman is a buggy mess and I don't recommend it, though I had my fun in it.