Rushmark is a 2D speedrunning platformer set in a cyberpunk underworld, built around short, fixed courses that a practiced player clears in under thirty seconds. There is no health bar: touching a hazard ends the attempt, and a restart is instant. The move set is small: run, jump, an eight-way dash, a wall kick and an area burst. The dash doubles as the main attack. On the ground it recharges after a short cooldown, but in the air the player gets only one, and dashing through an enemy restores it, so a line of enemies becomes a route across a gap. The game has ten timed courses, an endless Survival mode drawn from forty hand-built sections that speeds up the longer a run lasts, and three Marathons that chain courses back to back. Every personal best goes on a Steam leaderboard, and players can pull another player's recorded run off the board to race it as a ghost or watch it. A season ranking scores players across every board, and season standing pays out in cosmetic skins.