First enemy, killed by stomping- Goomba from mario.
First enemy I stabbed to death- A zombie from resident evil.
First enemy I shot. A guard from metal gear solid, it was pretty simple due to that syndrome they have. (The inabilty to see more than 5 feet in front of them.)
First boss enemy I killed- Bowser I guess, but then again he never dies, no matter how many times you dump into that lava pit.