* SPACE : Cancel a thrown grenade.
    * fire: left mouse
    * M: Return to Level Select menu.
    * MOUSE : Aim and shoot by moving the mouse and clicking. Set the power by dragging the mouse towards or away form the grenade's origin.
    * Q: Toggle rendering quality.
    * R: Retry the level.
    * Esc or P: Pause
    * movement: mouse