Yeah, there are some tricky timings, which weren't really intended but still left in the game. I also think I made the puzzles a bit too hard, which you can't really feel when you yourself know perfectly how to solve them and are just thinking how to make puzzles that don't seem too obvious to yourself.
For example, for the crossroads(which I guess is the room in the thumbnail) you need to keep holding left and down two rooms earlier, then in the next room you go on the other side of the wall and start holding right, and then you enter the crossroads by going diagonally down-right, so you can enter the room on the left by releasing down-right and starting to hold left at the right moment(which is a bit of a precise timing). Both left paths are red herrings, which seemed to make it "complex enough" for me, but in reality, it's pretty hard for others to figure out.
I'd actually love it if someone managed to beat this, there's a last set of intertwining rooms(that also involve shooting some monsters) when you enter the top-right exit of the crossroads, which are also hard, I guess, but I think it would feel great to figure it all out. If anybody tries it, here's some tips: keep holding buttons; when you fail, always think how you should have done; the first time you enter a room there's usually only one exit you can reach, so find it; when you get to a dead end, it's not the game laughing at you, they are essential parts of the puzzle.
But even though I made the rooms too hard, the thing that amazed me is that it's even possible to make complex puzzles with this simple idea of having just one input per screen. Maybe it could be expanded so much that I could try making a longer game? Maybe.
Sorry for the long comment, and sorry for the game being too hard.