Snow Bros.

Type GSXRZZRFZRCBR (QWERTY Keyboard)
or
Type GSXRWWRFWRCBR (AZERTY Keyboard)

This, will give you 99 lives and enable the following keys

N - Skips to the next level
B - To transform into BIG Snow Bros


Type EXUP during gameplay to be taken directly to the end credits sequence.