I'm enjoying the game. The movement is good and I like the level design. However, there are a few hiccups bringing the game down.
There are "hidden" checkpoints in the game which can help but also hinder. I climbed a cliff and jumped down to check the area, only to spawn lower down.
To make this a fully-rounded game, it needs a counter showing how many coins/slimes you have out of how many you need plus a level select.