Krunker

Krunker is a free-to-play game. Has an arena-style browser-based tactical first-person shooter game where usually up to 8 players join a lobby and shoot each other to death or compete over an objective. Games typically last about just 4 minutes, so it's perfect when you are waiting for your teammates for example. Krunker is a fun “pick up and play” type game. The game speed is lightning fast too. After you die in-game, you can respawn just about instantly which means there is very little downtime.