Interesting spin on the theme. I think that creating incremental levels, where the total number of "tiles" started small initially and then grew with subsequent levels, would improve the engagement. When the game first started I thought I had to count the total number. When I figured out I was supposed to count the total for each of the 3, I pretty immediately realized I did not have it in me to do that.
If you started with 10 tiles and then worked your way up to 200+ I feel like it would offer a developing challenge. Also having submit end the game early (instead of having to wait) and then showing the correct numbers would be great additions as well in my opinion. Nice work though