Press enter to choose a menu option, and escape to go back to the
previous menu. Press F9 to view in-game statistics, and P to
pause. Alt+enter switches between full-screen and windowed
The other controls are configurable via the "setup options"
menu. By default, the controls are as follows:
-Left and right arrow keys to move left and right.
-Under Windows, Alt Gr (right Alt) to jump and the space bar to shoot.
-Under Linux, the space bar to jump and left Alt to shoot.
-Right Ctrl to change weapon.