Each race has different strengths, weaknesses and abilities. Their cultures also effect how your colonists will react to the political decisions you make. The Uva Mosk are a race of environmentalists that get mad when you disrupt the environment, the Tarth are a warrior race who get annoyed about peaceful solutions, the Humans will riot in the streets if you're caught dealing on the black market with an alien race that once blew up part of Earth's moon, and so on. Some races also have more difficult to please morale like the perpetually-sickly Maug. Some make lousy warriors, some make amazing technology researchers and the bug-like Ch'Cht multiply like roaches leading to food shortages and the ever-pressing need to expand your colony.
They developed a pretty cool universe in the nice manuals they came with and there was a good bit of humor throughout the games, especially when carrying on diplomacy with, or trash talking, the other races.
Also as one of my favorite on-CD bonuses ever there was a humorous song that explained all of the races. Best tutorial: https://www.youtube.com/watch?v=j19mg4ci69A
It was kind of like a lighter more digestible Civ game. It's so cool and so completely overlooked. Both are on GOG now so play them dammit.
Unless you have nostalgia for it like me, I recommend the second one since it's basically just the same game as the first with more content.
