Nice concept!
I liked the game feel and gameplay too, I really think you should add coyote time to jumps tough cause sometimes I lose my double jump when I surpass the edge of the platforms.
At a certain point I got stuck on the ground (for holding the artifact for too long), and had to restart the game though, maybe you could restart it automatically when something like this happens.
Anyways, the game was nice, also with nice graphics and sound effects, good job on this :D