Cool idea. All three building options are quite fun to use. Using the reverse-gravity for the first time in particular felt quite cool!
There seems to be an odd bug where the music resets whenever the player presses the space key, which is troublesome for those who like to use that to jump.
And in the final puzzle of the cave zone, that long moving platform is able to push the player through that small gap. Pretty sure that’s not intended.
Stopped off at the checkpoint underneath those giant waterfalls as I couldn’t figure out how to progress, and some of the platforming had become rather difficult, and not quite in a fun way. In particular the spacing between that higher platform and the first of the small floating islands felt quite unfair, and I was only ever able to make it once. Implementation of “coyote time” would’ve made the platforming feel much better. The wall jump timing also felt a bit janky.
Despite my criticisms and my not finishing the game, I dad fun with it and thought it a cool idea. Making decisions as to which build option to opt for made for some interesting little puzzles, and again I thought the gravity switch was fun. Perhaps such puzzles came later on, but levels where you must place platforms, then switch gravity to utilize them, I think would be very cool. In any case, good job!