Thanks for the feedback, it means a lot to me. I just want to answer of your some points:
1) god damn I KNEW it. I had problems with those txt files before and didn't learn from past mistakes. I hope I don't do this again and I'll fix the README this afternoon.
2) I spent some time balancing the gravity scale with the rocket jump force, but I didn't worry too much about making him fall faster than that because I assumed that the player would just "rocket jump" down to the ground if he's impatient, and I didn't want anyone to spend a lot of time shooting down in the later part (maybe if I put both the shooting force and gravity scale higher... idk, could work out better). About the slide... I really could've solved that with a few lines of code, so that's on me (I'll certainly do it in future patches). And thanks for the video.
3) Yeah, you only take damage immediately when you enter the flaming ground node area. I'm still searching for a better way to implement that.
4) Yes, I noticed that you also used Godot. I played around with a lot of 2d engines (I honestly didn't like Unity2d, don't want to pay for the Gamemaker licenses... Love2d is ok, just not as good as Godot) and looks like this is the one that's gonna stick with me.