I think you have a sadistic streak. (Not that this is necessarily a bad thing in a game programmer.
Enjoying leading people on down long passages that go no where, propensity for gore, etc.
I like the HAL (I can't let you do that...) references, with the glowing eye. Can it execute the opening message a little more quickly? Or is this part of your sadistic streak, to eek out the letters one-by-one? (Maybe I'm just too impatient.)
By 'hitbox' -- I guess you are referring to where the collisions are registered? It was driving me a bit crazy trying to figure out what my tolerances were. It does seem like the aren't the same on all sides. Also, after turning, sometimes the little guy would move over or adjust one way or another, maybe just a pixel, but it was a little disconcerting, especially where it is so important to get the position just right.
Annoyingly hard to get through some of those doorways. I eventually came up with a way of using the diagonals so as not to spend half an hour tapping my keyboard as lightly as possible back and forth trying to get to line up just right. I find it hard to move avatar slight amounts. I guess having a shift-arrow for smaller movements would defeat the threat of the spinners.
Nice animation on the avatar, by the way.
Nice splashy gore and sudden noise => jumped in my seat a couple of times.
I wonder about the point at which you switch rooms. I can have only one pixel visible (and the rest in the next room) and there is no cross-over. Maybe you could cross over a little sooner so one could see where one is going? (Kind of important when across the way there might be spinners!) More important to see where you are heading than where you have been.
I didn't get if there was any special significance about clocks and time (from messages in first room). I didn't like having the game clock obscure valuable information. I think it is the x:1, y:1 block in particular, looking to go downward on the left side--can't tell if one is walking into a spinner or not because of the clock. Maybe the elapsed time clock can be somewhere else (have a dual location) depending upon where ones little guy is, so it doesn't cover anything adjacent to the avatar.
Stuff about key combinations and the kitty--it popped up no trouble for me when I found the message. I can't recall what I did exactly. When I got the message near the end about going back and looking again for it, I thought maybe I didn't really finish the process correctly, and I went back and killed myself a dozen times, trying things like positioning the kitty over the message or over the edge into the "void" area and committing hari kari.
Maybe if you HAVE found the kitty correctly, the message about going back can be different than if you missed it?
The very first message confused me, but maybe I am just too easy to confuse. It came up saying "hit X to read a message" and I did so and the message disappeared. I recall going back to it and trying again, and thinking, well, I guess this one doesn't have a message. I didn't realize that the instruction message itself was the message! Duh.
Thank you for an entertaining game!