Two knights share one keyboard, and neither of them has much finesse. Knockback Knights gives each fighter just a hop and a sword swing, and both actions push you around: swinging throws you backward, so your own recoil is a big part of how you move. You win by knocking the other knight out of the arena, and a hazard finishing him off counts just the same.
Use the recoil on purpose. Swinging while facing a ledge pushes you back to safety, but swinging with your back to the drop can shove you over it. More same-screen battles wait in Super Bomberman 4.