A game I actually followed the development of on /r/godot, and it didn't disappoint! Very tight and fun platforming. The rooms are well designed, there's a good mix of rooms that are satisfying to go through quickly and those that require you to stop and think for a bit. This game does a REALLY good job of introducing you to new mechanics without verbally explaining them, which I very much appreciate as a fellow platformer dev. The visuals are very nice (especially the animated intro) and feel snappy.
You must put out all torches in every room to move on to the next room. Red torches give you a dash you can use, kind of like Celeste. Other mechanics are introduced as the game progresses, like ghosts that re-light torches and keys that swap which blocks are solid like Mario on/off blocks. The levels are completely linear, you move from one room to the next and cannot go backwards, EXCEPT for bonus rooms. These branch off from the main path, but you immediately return to the path after finishing them.
It is a short game, I got 100% in about 1.5 hours. There's only one optional collectable for 100%, which are 15 bones that you get from 15 bonus rooms. These rooms are fun, and usually when you exit them you find that the room you return to is easier to solve from that starting point (though if you die/reset you go back to the room's original starting point, cancelling out this boon). Despite it being short, I think it's worth the price given the passion the devs put into it and the tight, fun experience.
My only feedback is as follows:
* Boss rooms should have a better indication that you died because the wall of death touched a torch, as I was really confused why I was dying at first.
* While they're pretty hard to miss and I never did miss one, it would be nice if the map displayed in which area you're missing a bone instead of just the total count.
* If you solved a room before entering a bonus room, then it should still be solved when you return from the bonus room. (Although, this could potentially cause difficulty if that room can become impossible to complete without ghosts to restore torches or something.)