Endings
Good Ending
The "Good Ending", triggered by the player rescuing at least fifty Mudokon slaves throughout the game, sees the Mudokons resolve to save Abe, and sees them chant together and invoke a powerful lightning bolt upon Molluck's head. With Molluck incapacitated, BigFace teleports to Abe, frees him, and teleports him out to a cheering crowd.
Bad Ending
Should Abe have failed to rescue at least fifty Mudokons throughout the game, the "Bad Ending" is invoked, wherein the few freed Mudokon slaves refuse to give aid to him. Molluck is given free rein to release Abe into a meat grinder, where he is instantly killed.
Subsequent games and media treat the "Good Ending" as canonical.
Bonus Ending
In the initial PlayStation version of the game, upon "perfect" completion of the game — completion with all 99 Mudokon slaves rescued — an extra full motion video (FMV) named "Guardian Angel" can be unlocked. The video depicts a captured Abe being harassed by "The Shrink", a mechanical creature with a sophisticated artificial intelligence. The FMV is notable due to its absence from the PC version and later PlayStation releases of the game, and its introduction of a new character to the Oddworld mythos. The character was reputedly part of an early advertising campaign, which included television commercials, but was eventually abandoned.
From Wikipedia.org