It would be nice to have an option to play without fullscreen, as I often write notes while playing, and like to have things side-by-side. I was able to use the OS controls to change it to be windowed, but built-in would be nice.
When first starting, the in-game display of controls feels too far away. I had started to experiment with controls & moved before I even noticed they were there. The layout display gave a general idea of what they were, but they were not really readable until getting closer. I had initially started at fullscreen, and it was in starting to write about this that I looked for a fullscreen toggle, so this was not a result of changing the window size.
I'm not a fan of the camera position. I'd like to be able to move it for a better angle. It could be free control, or perhaps several presets to cycle through. The perspective just did not work for my brain. With some practice I was starting to get a feel for it, then at the end of level 2, when you get near the covered areas, it shifted, and that completely threw me off. That was when I stopped.
You mentioned speedrunning, but there is no option to retry a level. Pressing Escape takes me back to the main menu, requiring starting over at the tutorial. This could use with a level select screen, allowing the player to retry any completed levels to challenge their best time. I played through the tutorial again to check if there was a best time shown, but did not see one. Also, the timer did not start back at 0 for the new run. If you are going for a speedrun game, then I would display the best time when replaying a level (and on any level select screens), and it needs to reset the timer.
The controls feel decent for the style of game. The level layout seems good, and the progression is good for a demo. This is not my type of game, but seems like a good start.