To everyone struggling to get past the spike walls: You have to damage the wounds on the dragon's body to progress. This is not explained in the game.
The game has a fun concept but the execution is lacking. As mentioned, the primary goal of the game is not explained clearly to the player, which means it's basically impossible for anyone to progress without just... trying random stuff.
The wall jump also feels very clunky because it isn't smooth, like in something like Celeste or Mario. Your velocity snaps directly to the reverse immediately.
It's honestly a shame since the concept of platforming around a giant entity is really cool, but this game needs more work and polish to get to that point, and I really hope it does, since this game has some interesting ideas to it.