I'd suggest a more clear listing (maybe capitalized string) of the game's functions in the game description. I sort of assume it's some story introduction so I skipped after the first line and jumped to the end. I was gonna say "What level selection?" before I notice you actually did mention how to access it.
I agree with squidly about the art direction, it's not that it's annoying but it just feels a bit..eh...let's just say the tiles of your choice are not complementing each other very well.
Not yet optimal, I'd say.
But other than that I appreciate the game. Music and enemy design are both very well done. The Clockroach, the Crawler and Vortex Painting are all very nightmarish in nature, excellent design! (Unlike DragonessUniverse below, I actually liked the Clockroach's sfx; each to their own, I guess.)
The last couple of stages are no longer about platforming, but more of brain teasers; either style is fun.
In some stages it seems you don't need every document to pass.
For example, Level 17.
(This is not the only stage, but the one stage I remember)
I can no longer reproduce this one but I noticed there seem to be occasions that a clip/paste would cripple you. You can no longer jump afterwards.
(I suspect it's a sort of glitch that you're actually getting stuck in a solid tile but the game still lets you move freely, just not jumping)
In stage 20, you cannot move the the lower right-most Vortex Painting. Clip/Paste will only invert its color.