Yup those were definitely some cute slimes. The sound effects were very poppy and adorable, but the music was a closer to reflection to how I felt on the inside while playing. It gets intense! I didn't feel like it was too difficult, though. Which is nice. I managed to clear it on my second run (thankfully). I also like how you didn't use any upgrades to communicate power scaling. It seemed more like the slime explosion radius increases with each level, taking out more slime with each kill. That was super satisfying.
Fun game! We definitely need more cute slime games in the world.