Duke Nukem Forever

This achievement is very easily done within the first twenty minutes of playing.

After defeating the first boss and making your way through the studio set, past all the talking and set pieces and finally punching the alien that breaks through your door you'll be able to start working on it.

In the first corridor, leading to the gym, you'll find bronzed statues of Duke and other trophies that can be picked up and generally thrown for a one hit kill ( bearing in mind that the achievement is for kills not hits, so pick up another object if they survive)

Inside the gym is a good opportunity to pick up the weights and dumbells to throw at a few more aliens. The best part I found to rack up throwing kills is when you're heading to the gun turret. There are plenty of gas canisters lying around that can kill a fair few enemies at once. It might even be worth your time reloading the checkpoint or dying as the tally still counts the kills.

These gas canisters are also useful for trying for the achievements involving "10 kills with environmental explosives" and, if you're lucky, the "kill 3 aliens at once"