Successfully complete campaign mode on the medium difficulty setting to unlock the hard difficulty setting.
Gray Alien in multi-player mode
Successfully complete campaign mode on the hard difficulty setting to unlock Gray Alien in multi-player mode.
Know Something We Don't?
You can submit new cheat codes for this game using our Cheat Submission Form.
Have We Been Fooled?
If you see a non-working or fake code in the list above, let us know by using our Problem Submission Form.