Ya that's all understandable.
The level is meant to be sort of like you're feeling your way around, but ya sometimes there's not enough contrast between the walls and the background, so it's unintentionally confusing.
Ya, the hands coming down and rainbow face means you've made a friend.
You can generally move on whenever you want to. There should be a drop at the end of every hallway. The game is sort of meant as a meditation of sorts, seeing as there's no way to lose.
Thanks for playing and the feedback :)