There are more secrets, although they're not really that awesome.
Basically, they're places that gives you a hint about a bigger level.
Like Utopica Minor, and there's another one that I can't think of, that has a way to get past a place, and a guy will tell you something. (Its a level with electricity, and green lights, and lasers. A bit like the ufo, and has similarities to the packet router from MAS2
EDIT: I looked it up, and that place is called strange place.