I'm loving the aesthetic. Low poly bright colors are my jam. I also liked the idea of moving mower wheels individually, definitely adds some complexity.
However, I didn't really feel the upgrading really fit with the idea of "dual purpose". It didn't feel like it meshed with the main mechanics, just sort of a side addon thing. Same thing with the menu music, doesn't quite fit with the mood of the gameplay. I also couldn't figure out what was forcing me to restart the level (though it's distinctly possible I'm just stupid).
Overall, good. Not great, but good. Another pass in the design phase, a bit more cohesion between assets and gameplay, and you really could have something great.