Ok, overall I really liked the game. It's quite short but that's totally understandable, and honestly it just shows I wanted to play more.
I think at this point you should add more slime types, each with a unique behaviour, but the game as it is now is still really enjoyable.
I'd also add an indication as to where the remaining slime will stay when splitting. I did get the idea at stage 5, so it's not necessary, but it won't hurt the game either.
The sound design is easily the best in all of the games I've played in the jam. Easily. So crisp.
The art is simple, but fitting the game, and it was a great choice of a color pallete.
The background music is also probably the best I've heard out of the 25~ games I've played thus far.
Very well done!