"The aliens of Gloom are clearly insectian, mostly arachnid and often aliens are portrayed thusly."
Exactly - there is little difference between the hatchy/kamikaze and house spider. The drone (was) a giant flea or grasshopper. All the Gloom "aliens" have 8 legs, like spiders. The aliens in Tremulous won't make as clear associations with anything
I don't have a specific basis for creating all the aliens, but hard carapaces and legs will be common. I'm just not adhering to a principle of "All aliens have 6 legs" or basing any particular alien off an animal.
I am not going to get in the habit of releasing models or visuals before they are done but here is one example:

Ok, it has 4 legs and scythe like claws - the posture is almost like a gorilla, but it's blue and it has a hard exterior shell. I haven't modeled this one yet so I'm not sure how close it's going to stay to this design.
Here is a shot of the hivemind in modeler:

Now I admit , it does share some qualities with an insect or crustacean - but I did not base it off any specific creature. I wanted to make some menacing, perverted and creepy.
So yes, it resembles an insect an more than a reptile/bear/goose/kangaroo, etc.
"Why couldn't you upload them to the page in the next update? That might get even more ppl interested."
In due time, I get focused on creating artwork and forget to upload. But you are right - we do need some new screenshots.