Oddworld: Abe's Exoddus is the sequel to Abe's Oddysee, following Abe's quest to rescue all 300 mudokon workers from the corrupt Glukkons' Soulstorm Brewery.
Overview
Created by Oddworld Inhabitants under the direction of Lorne Lanning. Released in November 1998 to the same critical acclaim (notably for its wonderful 2D graphics and graphically stunning cutscenes which were entertaining as well) as the first title.
Get the slaves away from the gas and snap them out of it.
A platformer with a dark sense of humor, Abe's Exoddus is considered a bonus title in the Oddworld series because it is not part of the main quintology. While keeping the same core gameplay as the original it adds numerous additions including the much needed quick save, characters having different emotions and some being blind, new enemies, and the ability to possess Paramite's, Scrab's, Glukkon's, and your own farts after drinking SoulStorm Brew and use it as an explosive.
You travel through several areas including the Necrum Mines, FeeCo Depot, Slig Barracks and the SoulStorm brewery itself.
Story
Abe's Exoddus takes off where Abe's Oddysee ended. Abe, the hero of the first game and liberator of the Mudokon slaves of RuptureFarms, returns home to a heroes welcome from all 99 Mudokons he saved. Clumsy as he is, he trips and is knocked unconscious. He is then visited by a vision from the "Three Weirdos". Abe is told about a new threat from the the Magog Cartel. He finds out their using slaves to mine Necrum, the sacred Mudokon city of the dead, to collect bones that they add to the ultra-addictive SoulStorm Brew.

Abe leading his followers to SoulStorm brewery.
Abe and a group of Mudokon's set out across the desert to find the SoulStorm brewery and free the slaves. Just as they are about to give up and go home they hear a noise in the distance getting closer and closer. Suddenly a huge train screams past them and it's heading right to the brewery. With new found hope they set off and follow the train. When they finally arrive at SoulStorm they climb the fence and enter. Just as they get in, Abe loses his footing, slips and falls down a set of cliffs, cutting him off from the rest of the group and beginning the first level of the game.
Endings

It's not fair! We had twice zee flavour!
There are two different endings in the game depending on how many Mudokon slaves you rescue. If you save 150-300 slaves, you get the good ending. If you save 0-149 slaves, you get the bad ending. Additionally, if all 300 Mudokons are saved, the player is rewarded with a concept art gallery, and if 276 Mudokons are killed, Abe is sent back to the FeeCo Depot with permanent invincibility.
Enemies
There is a vast range of enemies in Oddworld. Here is a brief description of them.

Pants! I need some pants!
Crawling Sligs
Sligs without pants or a harness. Despised by Glukkons, Mudokons and especially other Sligs, they are complete cowards and when threatened they rush to find a pair of pants.
The primary security force for all Magog Cartel structures. They use mechanical pants and normally are equipped with a machine gun.

Somethin' smells!
Flying Sligs
Same as Sligs but instead of using the mechanical pants they use mechanical harness with a grenade launcher.
Sligs best friend. Fast attacking creatures used as guards and back-up for Slig patrols.

Sloggie
Sloggies
Baby Slogs. Younger, smaller and not as fast as a full grown Slog. They can still take a nasty chunk out of you.

Fleech
Fleeches
Starting off as pets of Glukkons, they grow too big and are flushed down the toilet. Colonies now infest Oddworld's underworld.

Slurg
Slurgs
Pathetic, useless slug-like creatures. Not a threat but when stepped on they make a high pitched screech alerting anything in the area, normally Fleeches.
Fast, efficient hunter carnivores. They'll make short work of Abe, or anything else that looks like a tasty meal.
Scrabs are highly territorial and incredibly hardy predators that originated from the desert. Scrabs have beaks powerful enough to snap bone.
The big dogs of Oddworld. They own and control Magog Cartel. Greedy, ruthless and only care about them self. They won't attack you but he sure that they'll have a decent amount of armed protection.

Greeter
Greeters
A tin can with a huge smile. First used as self-promoting vending machines they now act as security guards after discovering they had the habit of electrocuting their customers.