I like that you can leave and get an ending at different points! It makes me feel better about putting down the puzzle, and acknowledges that I at least made it pretty far. I also like how each ending has its own emotional impact.
Acknowledging the player leaving a puzzle, in a positive way, seems like something that could be added to lots of puzzle games!
I didn't solve what I think is the final puzzle, but I enjoyed getting to where I did, and making it out with a chip of the artifact!