Okay, this is 100% 5 stars for theme, creativity, and gameplay for me. FUN! Very clever little mechanic that made be think. The pixel graphics are charming, and the music is lovely. It's hard to find a music track that doesn't get annoying sometimes, but this music is a perfect balance of pretty and engaging. Puts you in the right mood to solve puzzles, right?
I was intrigued by how you DO NOT want upgrades all of the time. It's actually easier to solve certain parts of the puzzles with shorter explosions, and that emergent detail was so freaking fun to discover. You find yourself counting exact distances to not blow up your gems.
The only "bug fix" I ran into was to consider having the character automatically end their move on an exact grid location? Like sometimes I'd over-run the corridor I wanted to go down, and be slightly frustrated that I had to back track. I noticed that you have some nice "auto correct" so if you're nearly in a corridor, it will slide your avatar onto the grid, but maybe that tolerance needs to be tuned up a pixel or 3?
One mechanic that I thought might be cool for a future iteration would be bombs that can destroy upgrades. I could imagine wanting to strategically keep your explosion shorter. Just an idea. Overall a very solid entry. Thank you!