Thanks for your reply, congrats on making it that far! Yeah, the mechanic of the dragon's ability could have been explained a bit more clearly. It has to have a clear line of sight from its head to a wall in order to teleport, any water would block that.
Hints (rot13) for that dragon section with the one-tile block and the small waterfall above the checkpoint:
Small hint: gur purpxcbvag vf cynprq gurer sbe n ernfba!
Medium hint: lbh arrq gb gryrcbeg hcjneqf
Big hint: lbh bayl arrq gur cyngsbez gur purpxcbvag vf ba