Abaron

There is a built-in cheat mode in this game that can be activated by typing in OUTLAW anywhere in the game. You can now use the [/] key to jump to the next level
and pressing the [I] will make your ship immune against hits. If you press the keys [1]-[7]/[F1]-[F7] you can choose the weapons for player 1/2.

Absolute Zero

Cheat mode:

Set the system date prior to November 1995. Start a new game and type magazine review (case-sensitive) to enable cheat mode.

Abe’s Oddysee, Oddworld

At the main menu, type in these codes:
Hold down SHIFT and press these arrow keys: up, left, right, left, right, left, right, down to view all movie scenes.
Hold down SHIFT and press these arrow keys: down, right, left to select any level.

Ablion

Visit the healer on the planet Iskai. Talk to her and end the conversation immediately. In most cases the healer will give you a blue magic potion worth 16.6 gold pieces. Repeat this untill you have enough money to buy weapons etc.