My philosophy is to make a fun mechanic first, and then make fun levels that get as much fun out of it as possible. Happy to see that paid off! Also, even though the graphics were simple, I made sure to use a consistent color palette (from www.colormind.io), and I think it looks great as a result (at least better than my previous games!)
Those sound effects are actually placeholder, and I was thinking the same thing about harmonizing with the music! Funnily enough, any time I had to work on the game, my pet parakeets were being loud, so I couldn't record any sound design! LOL, maybe next time.
Interesting note about the first levels. I envisioned a brief story that would start off and conclude the game, but it ended up getting scrapped. But it involved the first level being laid out like a house with rooms, introducing the mechanic. I guess without that, it just looks like a messy first level. Even so, you're right that it's important to explain the win/lose states early.
Thanks for the awesome feedback! Also I'm glad you liked reading my game description. I'll be sure to try out your game too!