Armed Forces.io is a browser multiplayer shooter with a military theme and several game modes across a set of maps. It has the movement flourishes that browser shooters have converged on — sliding while running, quick weapon swaps — and matches that start immediately without an account.
It sits in the same space as Krunker and Blockpost with a slightly more realistic art direction, and it runs well enough on modest hardware to be a viable school-laptop shooter.
No — you can join a match immediately. An account tracks your unlocks and stats.
Several, including team and free-for-all modes across a rotation of maps.
Yes — it runs in the browser with nothing to install and needs only a live connection.