Great concept and execution!!
Would have loved to play more of it (played the full version you linked) but the game feels so slow and difficult to get in managed to get three artifacts.
A tutorial would have helped the game so much, coz I thought we had to use pickaxe on the bones and after some playthroughs figured out the white things are clues and not stones :D
Also noticed the music getting faster and faster which is a nice little touch but it gets irritating after the 15s mark. You could make a track keeping the time constraint in mind and edit it and then add it to the game maybe. You would have a lot more control over how it sounds.
Overall, a really good game and with enough polish and balancing I can see people investing hours in it..
Kudos!! :D