Shoot aliens


               keyboard

  A stop  S shield     move  < >  move

Space* * * * * * * * * * * * * * * *fire


Ctrl-P * * * * * * * * * * * * * *paddle

           button 0 to fire

Space* * * * * * * * * * * * * * *shield


Esc* * * * * * * * * * * * * * * * pause

Ctrl-S * * * * * * * * * * * * * * sound

Ctrl-V * * * * * * * * * * * * * *volume

Ctrl-R * * * * * * * * * * * * * restart