This was fun!
I've seen games like it before, but never played one. I found the puzzles to be challenging but achievable, which was just right for me.
The core mechanics are well-introduced and easy to understand. New elements are added at a good pace, and visual cues make it easy to intuit what they do.
The exception for me was the timed zappers on the last level: at rest, these looked sort of like buttons, which they're not; then when they flash, they look damaging, which again, they're not; then when they turn to a solid block of colour, they don't look especially dangerous or important, which they suddenly are! Of course, this was easy to work around with trial and error, so it certainly wasn't a big issue.
The art was simple but pleasing. It looks like the time was invested on the slimes over the rest, which was a good choice.
Overall, I liked it very much. Thank you!