One Must Fall: 2097

Advanced Options:
On the first screen (The one with the 1,2 player mode, configuration,
gameplay ect) hold down the keys 2 0 9 7 at the same time for a few
seconds. Go to the gameplay screen and there should be an advanced
options screen.

Color Change Keys:
In one or two player mode pick your pilot. At the robot screen
select the robot you want. Don't press enter yet. By pressing
the 1, 2, and 3 keys you will be able to change the colors of
your robot.

Easy Win with Shadow:
Buy or choose the robot Shadow. When you've stunned your enemy,
quickly do the shadow grab (Shadow's shadow holds opponent from
behind). Now hit your enemy however you wish and when they get
back up they will be stunned again. Repeat this process for an
easy and profitable victory.

Heavy Metal:
At the title screen, type REIN. Whenever you hit someone scraps
of metal start falling from the sky.

Play as Nova:
To play as Nova in 1 or 2 player mode, choose a pilot then at
the robot selection screen press F, F, F, D, B, B, U, B, U, Dx11, F+P.

Pyro's Moves:
Here are three of Pyro's best moves.

Fire Spin - Down + Punch
Jet Swoop - Up, Down + Kick
Thrust - Toward + Punch, Toward + Punch

Shadow's Specials:
To perform the Shadow Grab, press Down, Down, Punch.

To do his Air Grab, jump then press Down, Down-Forward, Forward and Punch.

Thorn's Special:
To perform the Spike Charge, press Forward, Forward, Punch.

Jaguar Secret Moves:

Concussion Cannon: Down, Back + Punch
Overhead Throw: Toward + Punch

Secret Test Sound Effects in Configure Menu:
Press Alt+S+F all together. Shareware only goes up to around #75
with gaps in the middle.