Deathmatch is a game mode first introduced in v100 Alpha. In Deathmatch, teams fight against each other trying to kill the opposing team more times than they get killed. Up to 8 players can play. Deathmatch allows you to pick from 4 teams, green, red, blue, and yellow.
In the "maps_dev" folder you can find a map called Stormynight. It was most likely made by Frall.