Hold down CTRL+C until you hear the chime, after which hold down:
CTRL+H - Activates the Hand
CTRL+I - Invulnerable
CTRL+L - Max out your lives
CTRL+N - Turns the Hand and Pterri off
CTRL+O - Overdrive
CTRL+P - Activates Pterri
CTRL+S - Turns all the birds into eggs