Biofreaks (N64)

Dirty fighting:
Pause game play during a match, and disable shields. Resume game play and hold A while attacking.

Taunt opponent:
Press C-Left + C-Right during a match.

Alternate view:
Hold Left and press Start during game play. Hold Down and press Start to return to the default view.

View version date:
Press C-Left immediately after powering on the system. The sound of laughter will confirm correct code entry. The date on the title screen indicates when the game was completed. Note: C-Left may have to be pressed a few times.

One hit fatalities:
Start of moving in close and pressing towards, away, away and then the following c buttons:
Minatek: C-Left + C-Down
Zipperhead: C-Right
Ssapo: C-Up + C-Right
Psyclown: C-Left + C-Down
Sabotage: C-Up
Bullzeye: C-Up
Delta: C-Down
Purge: C-Up + C-Right