Condemned 2 - Bloodshot

This achievement is for killing ten enemies with your fists. This can be done in Ranked or Player matches.If you use a finishing move to kill an opponent after you’ve beaten them, it won’t count towards this achievement. The achievement will unlock after the tenth kill. If you are curious as to how many kills you have there is an achievement counter that you can access by going to "extras" on the main menu then selecting "achievements".

I found the fastest way to do this is to set up a private deathmatch with 2 people on the map Lodge. It is a very small map and you should be able to easily get 10 fist kills within 5 minutes.

Can be done in both player and ranked matches. Easily done in Deathmatch mode and just whailing on people with your fists. If you see two people fighting try to intervene to take them both down. The achievement will unlock on the tenth kill.