Oh, you reminded me, I was going to mention that I appreciated how one of the levels was extremely close to sokoban.
If the game was fleshed out more without the constraints of the jam it would be cool to see the levels grouped into several worlds by their theme, one of the worlds being all about puzzles which are almost sokoban. I can see lots of room for many more puzzles within these mechanics. I do think the three types of slimes are enough on their own to support that without needing more types.
I also wanted to mention that I liked how the game highlights which squares the slime is able to move to, but I did notice that it doesn’t highlight which slime is currently active, which can be misleading when I have a blue slime last clicked and I can’t tell because the shaded squares are all the way at the other side of the screen. That would be a good improvement if you plan to work on this further. I think it has a lot of potential, and for the most part would just need the levels.