I think this is my favourite game of the jam, and I'll be surprised if I find something better. The mechanics and level design were great, and little existential text boxes for the slimes really help the narrative. Good music and SFX (especially the confused little confirmation sound off the slimes when you call it - it reminded me a bit of Oddworld.)
I'd totally play/buy this if it was a full release - also similar to Thomas Was Alone.
If I had one criticism, as others have mentioned, the jumping collision and the responsiveness of the jump didn't always feel like it worked.
Just an amazing use of theme and I have no idea how this was made in 48 hours!
Oh also I love the animation, especially as your slime grows.