Space Station: Silicon Valley

Go to the game or stage selection screen and press the following button
combinations. After entered the codes, select a saved game or level
and press Left.

Note: If the codes are accepted you should hear a ping sound.

Additonal energy: Press C-Left, L, Z, Down, L, Z, C-Left, C-Right.
Asteroid stage: Press Down, Up, Z, L, Down, Left, Z, Down.
Desert stage: Press Up, Down, L, Z, Down, Left, Z, Down
Europe stage: Press Up, Down, L, Z, Down, Up, Z, Down
Final stage: Press Up, Down, L, Z, Down, Right, Z, Down
Ice stage: Press Up, Down, Z, L, Down, C-Right, Z, Down
Joke 1: Press Up, L, Z, Down, Left, Z, Down, Up
Joke 2: Press L, Down, Z, L, Down, Up, L, Left
Joke 3: Press Z, Down, Up, L, Right, L, Left, Right
Joke 4: Press Left, Right, Z, L, Left, Z, Right, Left
Jungle stage: Press Up, Down, L, Z, Down, C-Left, Z, Down
Hidden stage: Press Down, Up, Z, L, Down, Left, Z, Down
Stop camera in wall race: Press Down, A, C-Up, L, C-Down, L, Left

Different intro:
After the DMV man appears, hold B or A and power button on
the Nintendo 64 system

Transform Evo gold on the last stage:
Find all 390 metal orbs