I am getting flashbacks to Slime Rain hehe
Great game though, the movement is a bit slippery and can be worked on but I like how free it is. Sound effects can also certainly be improved, I don't think some of them like the ding sound definitely don't fit the aesthetic you got going on. Having numbers as keybindings for upgrading is also a bit awkward.
I really love the slime death goo though, especially how it matches their colour. It was such a nice touch =)