Your line never stops turning and leaves a solid trail behind, box your rivals in and be the last one still moving.
Each player drives a constantly-moving trail that you can only steer left or right. Crash into any trail, the arena wall, or yourself and you're out for the round; survive longest to take it. Optional pickups speed you up, slow you down, thin your trail, clear the field or let you phase. A once-per-round phase punches you through a single trail you'd otherwise hit, but it tears a gap in your own line.
Curve War recreates the snaking multiplayer duel that has been a hot-seat favourite since the mid-1990s, when Achtung, die Kurve! spread across European computer labs and student halls; it has been rebuilt so many times under so many names that no single version is definitive.
The rule that makes it work is that you cannot stop turning gently — there is no straight line, only a curve you steer left or right, so holding a course is itself an act of control. Trails are permanent walls and the arena only ever fills up. Occasional gaps in your own trail are the one mercy, and the standard tactic — wrapping tightly around an opponent to shrink their space — is also the fastest way to run out of your own.
Curvewar is an original, free browser version of the classic light-trail survival duel, adding pickups and a one-shot phase move for local hot-seat or online play. No install required.