There's tonnes you won't know just by playing the games, LawnChairFire.

I'll bet you won't know how Abe's Moon was formed or why the rift between the Glukkons and Mudokons first occured, or the name of the autobiography Aslik released to cash in on his popularity, or who drew up the Oddworld Map.
OWI rewards it fans with so very much, but really the only ways for them to do that is over the Internet and going to see them in person. Having been a part of Oddworld's online fan community since 1999, many golden nuggets of information have been taken in by my eyes.

Hope that helps.
To specifically reveal how we knew those creatures were Gloktigi: ex-Inhabitant game designer Paul O'Connor used to write a designer diary while Munch's Oddysee was being developed. Gloktigi were designed during this time, and he uploaded a small scan of the designs of the Octigi Family, including their ‘names.’