Cool idea! Timing the attacks with the board was interesting, if a bit difficult. It would be cool if there was more control over what gets added to the board and where. It would also be nice if there were more sound cues and maybe warning indicators for the spike balls, since you often have to run to the edge to pick up a gem.
EDIT: I had to go back for a few more runs. Actually quite a cool concept. Had some interesting moments where I would deliberately avoid a heart on the ground when I was at 3HP, giving an additional thing to dodge. My best score was 29.