The code to turn the characters into shrimps is 025,
entered using the A button, bottom C button and right
C button on the Matchup screen. Enter 273 to activate
Stealth Turbo mode in two-player games. In this mode,
neither player can see how much Turbo power his of 
her opponent has remaining.

Enter 616 on the Match-up screen to max the blocking
ratings for both players.

Enter 937 to have free reign to goal tend at will.

Enter 390 for the No Pushing Option. 

Enter 048 for no music.

Enter 461 to use your best moves.

Enter 552 for Hyper Speed. 

Press Y eight times and A twice on the Match-Up 
screen for802 to come up to max out your team's 
Power ratings. Press Y once and B twice on the 
Match-up screen for 120 to come up to increase your
passing abilities to the max. Press Y six times, B,
and A six times on the Match-Up screen for 616 to 
come up to become good at blocking.

When the screen changes from Team Select to 
Match-Up, hold Left on the Control Pad and press 
Turbo three times. The code box will flash and 
you'll go to the game on top of an apartment 
building. To access the special Rooftop at Night 
court, press Left, Left + Y, Left, and Left + Y on
the Match-Up screen.

Press L, R, Select, , Start, Up, Down, A, B, Y, 
and X on the Match-Up screen to play in the Amazon.

Go to the options screen then hold one of the c 
buttons and press r button, this will bring up 16
zeros at the bottom of the screen. The bottom c 
changes players head size. The left c changes the
next two zeros it affects players size. Top c 
changes 5th and 6th zeros it affects players 
height. There are tons of combinations.

Here are dupliate and hidden players:
NAME PIN
kidd 0000
glennr 0000
hgrant 0000
kemp 0000
smits 0000
pippen 0000
motumb 0000
webb 0000
stackh 0000
malone 0000
rodman 0000
ghill 0000
ewing 0000
cliffr 0000
webber 0000
mursan 0000
davidr 0000
starks 0000
dream 0000
johnsn 0000
rice 0000
mourng 0000
ahrdwy 0000
elliot 0000
miller 0000
japple 6660
jc 0000
minife 6000
mxv 1014
danr 0000
jason 0729
nobud 1010
divita 0201
jfer 0503
marty 1010
jamie 1000
patf 2000
quin 0330
marius 1005
turmel 0322
jonhey 6000
carlos 1010
nick 7000
mortal 0004
kombat 0004
perry 3500
munday 5432
danicl 0604
morris 6000
shawn 0123
root 6000
nfunk 0101
amrich 2020
eugene 6767
bardo 6000
eddie 6213
mednik 6000
sno 0103

Here are matchup screen codes:
025 baby mode
048 no music
111 tournament mode (tougher game)
120 fast passing
273 stealth turbo meter
284 maximum speed
390 no pushing allowed
461 unlimited turbo
552 hyper speed
616 maximum blocking (2 player only)
709 quick hands (maximum steal)
802 maximum power
937 legal goal tending

The powershot is A and down C