Duæl

A two-player-only Competitive/Cooperative arena shooter. Challenge a
friend! Get the high score! Screw your opponent! But remember, if the
enemy overruns your opponent's world, they will escape into yours.

Controls:

Player One - Keyboard, twin-stick style. WASD, IJKL

Player Two - Mouse, turret-syle. Move to aim reticule; Left click to
shoot; Right click to swap with player 1 and steal their powerups.