Press F9 and type one of the following codes, then press Enter:
Level skip: next level
Level select: load level [1-99]
Toggle God mode: god
Remove damage: set damage 0
Destroy all opponents: destroy all
Get indicated number of bullets: set bullet [number]
Get indicated number of missiles: set missile [number]
Get indicated number of depth charges: set dc [number]
Reload current level: reload level