Black holes show up whenever they feel like it, basically. Infinity doors are linked two way, very simply; secret shortcuts.

Five warps! That tells you something about the next big door

Wow the screen rotation element for the valve was pretty novel. I like how this game uses perspective, and also the visual design is cool.

I really liked how you didn't use the map at all in the first few episodes and just explored freely. ...but it seems you simply didn't understand how to use it at the time :'D Fast travel animations are there mostly because it's loading something. Better to look at an animation than a black screen for a minute if it's loading :P (it could be more optimised and load faster, though, I would imagine)