Cave 10 Reinventing the Wheel - Exactly intended, good job
Classic 4 Humble Bundle - Hmmm... I spent so long thinking about a solution that also works for NeoClassic that I missed something a lot more straightforward. Given that this level is actually significantly more difficult and precise in NeoClassic, I think what I'll do is repurpose the level idea for QFK1 in a way that works a bit better for L1, and come up with yet another replacement level for this pack, something that's a bit more friendly to working in both L1 and L2.
Classic 5 Overflow - Now you've got the right sort of idea
Not totally fussed that you might be able to spare a builder, maybe it opens a bit of a backroute in NeoClassic where the step height is larger, but whatever.
Classic 8 Escort Mission - This level is going to be the death of me haha, but... I've had a brilliant idea that I should have seen earlier. Expect a slightly more unexpected change to this in the next update.
Classic 10 The Water Tower - Oh man, this makes me quite sad, this is going to be very hard to deal with as it is hard to change anything here without messing up the intended solution, given the terrain restrictions in L2. BUT, I think I might be able to come up with something.... Will need to test it.
Medieval 1 Introducing: Medieval - Exactly intended
Not sure if it's just hard in general or if this is hard because it requires you to first learn a number of important interactions. I do honestly try to keep these starter levels somewhat simple but in some cases it can be hard to have exactly one of each skill work and have each skill show off what it does while still being easy.
Medieval 2 Joust Duet - Exactly intended
Medieval 3 Ramp It Up - This backroute should be an easy fix.
Medieval 4 Roll With It - I know exactly how to fix this, although it does make the level slightly less interesting.
Medieval 5 Laying the Foundations - Bah! I knew you could turn around on that decorative little lump near the dragon but tried to make it work and couldn't. I must say your solution is pretty smart, but unfortunately it will have to go, and I know exactly how to do that.
Medieval 6 Going Full Circle - OK that first arrow is very clever
Your solution is largely intended and I can't see a way to fix your solution anyway so it stays
If you are wondering about the rollers, the intended solution is for the first arrow to be on the wall coming down from the ceiling where the second slider shimmies on the ceiling, slides onto the arrow, and rolls off. This leaves you one shimmier less, so the third slider, when landing on the last arrow, rolls off that instead of jumping.
Medieval 7 The Castle Cellar - Yeah this is pretty much correct
I am fine with the way you did this, only some small details different from what I do.
Medieval 8 Castle Invaders - Aaaarg! Looks like that little wooden overhang I added onto the first castle really did open up a backroute after all! Athough I think I also see another backroute issue with what you've done so will have to make some further changes anyway.
Medieval 9 Crate Expectations - A backroute I'm afraid, but one I know how to fix.
Medieval 10 Medi-Upheaval - OK this is annoying because I tried to pull off exactly this but couldn't get it to work, not considering that you could leave a very slightly unclimbable ledge and then mine it later. So I was really close with preventing this but it wasn't to be!
Sports 4 Rise to the Challenge - Bah! But I think it's fixable.
Sports 5 Tour De Farce - Yes this is closer to the right solution, but there's definitely an unfortunate issue here with trying to attach to the underside of a platformer in progress, which is definitely not intended. I think I can fix it.
Sports 9 The Home Stretch - Good grief the backroutes will never stop for this level hahaha. I feel a bit dumb for this particular one though.