Deathmatch is a mode commonly found in all FPS games.
Commonly referred to as One Man Army, there are no teams and it is "every player for him/herself". A player is against many others in a race to achieve a set kill count goal before each other.
Description by MFGEdit
There are no friends, every player poses a threat. Kill everything in your way and trust no one. You can score many ways - by killing or wounding your opponents and even by healing. The player with the highest score at the end of the round wins the match.