Aliens are currently very hard to learn for noobs, as the game denies them the practice.
Take noob humans. Yes, they are confined to riflemanship most of the time, but they still learn the most essential skills as riflemen: aiming, dodging all classses of aliens, so they aren't lost when they can afford a bigger gun.
Now take noob aliens. They're similarly confined to dretchendom, but they have much harder time learning how to use higher classes: they're too different from dretch: you have to click to bite, dodging is completely different, so noobs generally lose them in a few seconds after they gain them, having to earn them again (it's most likely hard for them, since they are still, well, noobs and don't have much experience with dretch either, and it only gets worse as the game progresses, since dretches become less and less useful).
