I've seen a lot of different entries have various web-built issues, so definitely not a unique problem!
Gosh, yeah, I totally see the scale of the challenge - it sounds like you have a really clear vision of what you want it to look like, and hopefully outside of jam-crunch that'll be fun and easier to implement. A kitchen level as a starting point sounds ace, and there's so many ambient kitchen noises to play around with to pair with that.
Yeah, that sounds helpful, there were times where I wanted to bait a slime slightly towards/away from an edge to make getting past it easier, and an indicator would have made that clearer.
Not specifically, I think the camera positioning was good - I think I was wondering if having fewer overall platforms would make it easier to navigate, and maybe also make the enemy/obstacle density feel higher. However, I think having heard that you're considering making the platforms more unique, that would probably help with the navigation too, so making the level smaller might not be a necessary suggestion, on reflection! It's much easier to remember that you took the drop at the rolling pin than it is the 'slightly wider platform'.
Ooh nice, I've never been very musically-capable, so I was still very impressed by it regardless.
A change in the enemies' animations sounds like a great idea, that would communicate that they've been affected very clearly and also hint at how they might behave as a result, very effective design!
Glad to hear they might have been helpful - I've only played a few platformers, generally more 'casual' ones, and never designed one, so please do take my feedback with a grain of salt. That sounds great, I look forward to it!