Overall, this project is quite pleasant to play and looks very promising. I love Trix's art, and it creates great atmosphere together with the music. The gameplay is enjoyable, as the controls are surprisingly comfortable and smooth for a game of this kind.
There are some things that require some tweaking for better experience:
- Spike hitboxes. Big spike hitboxes make it really easy to take damage in a game where you don't always have full control of the character. Also, in some narrow passages they make it almost impossible to stay undamaged. Perhaps it would be a good idea to decrease the size of their hitboxes.
- Boost orbs (or whatever they are called). I think they are an interesting mechanic, but they work a bit janky. I suggest moving the character to the center of the orb when touched, so that it boosts you in the right direction (kind of like Celeste's bubbles).
- Some passages work weird or are closed, so it is a little confusing, especially on the first playthrough (I am still confused by that passage to the right on the Screenshot 2 that loops you to the same room).
I also have a suggestion: separate checkpoints from bubbles. Having a checkpoint in every single room kind of removes the challenge. Instead, it might be a good idea to place a checkpoint every 2-4 (or more) rooms, and leave the bubbles just for the temporary safety. Also, consider making a checkpoint restore all of your health.
I hope my feedback will be helpful for you. Good luck with further development!
(P.S. My current speedrun record is 00:47:61!)