Krow
Crowman
yeah, there are warp zones. Some random warp zones whereas some are used to unlock characters. eg, Commander Video in the above screenshot.
The random ones are all glitchy and fun. I've been playing again. Reached Rapture worlds now. This is the first time I've got this far. But it's getting extremely tough now.

The difficulty of the last levels look unreal. The dark world levels of later chapters look more or less uncompletable. The dark levels of chapter "The Rapture" and "The End" seem like a joke by devs(heck even the light levels are hard to complete)