Hey wow thank you for your feedback, definitely wasnt expecting people to engage this much. I mainly put it up because my friends artwork was so incredible. But to your question: yes that's all for the little demo. But once I study some more level design I think it'd be a waste of these wonderful assets to not make a more polished set of levels. Any tips for toning down difficulty? I know it's the most common issue for newer level designers
Maybe just some more quality of life to start, like how many lives you have at this moment, how much floor you still have to slime. A checkpoint system would definitely reduce difficulty, could reduce it too much so would need to be placed well.
Also do the disappearing platforms come back after a while? They should just in case one misses a jump but still survives.