Battleroyale

Battle royale in a browser strips the format down to what actually made it work: plenty of players, a shrinking space, and knowing that everyone else wants exactly what you're after. That's it, and it's enough.

Smash Karts is the standout, combining driving and weapons in short matches that rarely outstay their welcome. Sworded.io - Spin and Rub. and Push.io are more direct about the elimination, and ColorWars.io - Conquest Game makes it about territory rather than kills. Ragdoll Battle Royale! Throw Down the Enemy! plays the whole thing for physics comedy. None of them need a download or a forty-minute match to be worth starting, which is rather the point of playing one here.

There are 7 free games under this tag, all playable in the browser with nothing to install, and none of them need a download or a forty-minute match to be worth starting.

The multiplayer shelf is .io Games, and Arena Games covers everything fought in a confined space.