My goodness, this is my favorite game in this entire game jam! I literally played it over 20 times, and that isn't an exaggeration. For over an hour. That is how fun this was.
I loved the physics, the way I could yeet the slimes around and smack them into one another. I knew what I was doing, the different types of slimes were amazing, and the boss fight was top-notch. One of my favorite things to do was to find the random items and throw them into enemies until they broke. The theme of the jam was prevalent throughout the game, and I loved every second. I couldn't beat the game though, not due to bad game design, but because I'm not good at it :)
The sound! The MUSIC! Epic, made me feel like a super cowboy ninja/exterminator. Brilliant.
I would suggest adding a health pickup or some way to transfer goo into health because having only a set amount of health per level is hard. I would also suggest that you keep the little gooey enemies spawning at least until all the brain/maco slimes are all dead because there is no way to kill them if you are out of goo and you don't have any items left to throw in the level.
The biggest thing I didn't like was that you had to start all over again if you died at any point. Checkpoints would mean a world of difference!
Dude, seriously, if you put this on steam, added more levels, more story, and polished it up, people will pay for it. I know I would!