Player 1 uses WASD to move, F and H to rotate, and T to fire. Player 2 uses IJKL to move, the left and right arrow keys to rotate, and the up arrow key to fire. The bolts do 1 damage each, so the first to land 10 on the opponent wins.
Might add heat and different 'Mechs with separate agility and health values, as well as different weapon sets.