I love the art style, it's a hand drawn look but very clean and pleasing to look at. I was surprised by how quickly I picked up on combining the colors and hurling them at matching colors. Simple but very fun and addicting, great job! :)

I got 14700 ^^. I like that you have a consistent art style, it reminds me of doodle jump. I also think the way your slimes merge while moving your mouse cursor is a pretty fun mechanic, which can increase the skill required as you have to carefully time it.

I do think the game would be better with a minor improvement. Right now if you get a pattern like this:
X
   X X

Putting a slime where the X is only deletes either the top or the left, it should be seen as part of the chain, making it easier to fill up gaps.

Oh I saw this artwork on the discord, I like the art style! Also fun to play! :) At first I was like how do I get the leaf? Then I combined lightning and water! Brilliant! :) 

Fun game!