Remember how in Unreal Championship 2
the lore says that the Bio-Rifle fires tarydium sludge? Remember how in Championship 2 the sludge was alive?
Immulsion is just a shitload of tarydium all in one spot, possibly mixed with some other stuff, and with a baaaaad
The humans of Seras/Ceras/whatever are colonists from the main Unreal storyline who crashed on Seras a long time ago and lost their databases on much of the Unreal 'verses tech during their landing, hence they have laser satellites but forgot how to make long-range starships and FTL drives.
Further minor WMG: The Locust had no
technological capability until the humans arrived and the two went to war, although they probably domesticated creatures like Brumaks before then.