Really liked the rocket jump mechanic, especially that you followed through with it and build your levels around the characters skills instead of just leaving it a gimmick. Same goes for the teleports! The leveldesign was very good and challenging. I loved the last part of the level where you need to go up while dodging all those spiderboos bullets :D
You also implemented the learning by doing thing very vell. First I thought "WTF firepit?" but then I went "AAH rocket jump!".
Some minor things I did notice though were:
1) The readme file is mangled up in notepad due to unix encoding. I know that notepad is not quiet a very useful texteditor, but I think for the majority of players on windows opening txt-files default to notepad. Just a thing to keep in mind!
2) The jump itself is just a tad to floaty for my taste, meaning that the character stays a little too long in the air after jumping up. I think you maybe did this for balancing reasons to make the rocket jumps easier? Reducing the slide on the ground when the character is stopping and falling faster after jumping up can increase the responsiveness and "tightness" of a platformer. A GDC talk that helped me a lot on our current platformer project is linked at the bottom
3) One only takes damage in the firepit when not standing still (don't know if this is on purpose).
4) Cool that you also used Godot for your project! :D
All in all very good level design and cool mechanics!