Bio F.R.E.A.K.S.
Creation Date
To check when your copy of Bio F.R.E.A.K.S. was created, quickly press the left C-Button immediately after you turn your system on (press it rapidly a few times to increase your chances). But you must stop pressing the button in order to view it. You will know if it is done correctly by the sound of someone laughing.
Credit For Code Goes To: Cowen Ashberg via IGN64.com
 Creation Date
 Fatalities
 First Person Fight
 View
Fatalities
These codes are for the default settings
Keys:
T = press the direction towards your opponent
A = press the direction away from your opponent
LP = Left-C
RP = Up-C
LK = Down-C
RK = Right-C
MinaTek:
Headspit - T-A-LP+LK(close)

ZipperHead:
Buzzcut - T-A-A+RK (close once opponents arms are gone)

Ssapo:
Headevour - T-A-A+RP+RK (close)

PsyClown:
Cut in half - T-A-A+LP+LK (close)

Sabotage:
Decapiblast - T-A-A+RP (1-3 steps away once opponents arms are gone)

BullzEye:
Backhandecap - T-A-A+RP (close)

Delta:
TorsoShears - T-A-A+LK (close)

Purge:
Mutilator - A-T-T+RP+RK
Credit For Code Goes To: Duros Bith via IGN 64

First Person Fight View
To switch into a first-person fight view press and hold left on the digital pad and then press the start button. To switch back, press and hold down on the digital pad and then press the start button. The code can only be performed once a fight has started.
Credit For Code Goes To: IGN 64