Regardless of ass no one wants that worm head looking at them. It's disfigured to say the least. The fact that the worm is in some sort of space suit is even worse, meaning that it could literally be some sort of worm and all the ass is just the suit.
Gex is gex, what else can be said. Most of the "ass mass" is already seeable, and gex is historically more trustworthy.