Took me a while to understand what to do. But once I understood, I continued until reaching the cow. I enjoyed playing it.
If you have only one thing to change, that would be readability of the main action. Damages did not show up so I did not understand that what I was doing was damaging the tiles. I believed for several minutes that only the red tile could be removed. If there was only a visual indication when a tile has damages (maybe several steps to show how much for the yellow tile but that another level), it would have ease the first minute engagement. If I did not see the previous comment, I would surely stopped the game.
However, really nice work for a first game.