1) It maybe just me, but the second switch palace seems 10 times easier than the first one: You basically have just to dance on the disco and get trolled once, whereas in the first one you can die nearly everywhere. Maybe simply interchange the levels?

2) Alot of people seem to be surprised by the sudden difficulty-spike in the beginning section of "2.2 Fire Brigade". Even upon playing the hack again, i can't exactly pinpoint, what causes this... Perhaps the sudden timed/mid-air shell jumps all within other obstacles? Could insert a (non-obligatory) training level for beginners.

3) "2.3 Chip an' Dale": The first turn block in the second half can be cleared without purple blocks. Just jump on the second naked Koopa to hit the turn block and go on. It's not a problem since the mole acts as an autoscroller, just wanted to let you know. (Although if you want to force the use of the purple block, you might edit a kaizo block under the turn block?)

4) In "3.1 Window cleaners" the first "guided rope" is somewhat glitchy. Sometimes when i grab it, it goes on track, but i stay where i grabbed it and fall to death (or can only regrab it on the low end). I tried to replicate this, but don't know, if it's due to p-speed, pressing weird on d-pad or grabbing to high.

5) My main grief, relly:
If you only change one thing to vers 1.5 please let it be the following:
In "Sea Scouts" we go through: a) fish wall, b) chuck forth and back + killing, c) Luring Rip van fish to the left. At best pace this takes 50 seconds! Please laugh at me, if i did anything wrong, but that's ridicolous to just die to item swimming afterwards, especially if the time from picking the block to going right is so tight. I will not spend 1 minute on every retry, sorry, i value my time somewhat, especially if the first part of this isn't even difficult. (I used savestates (not proud) and in this case not because i don't trust my abilities, but because i lack interest in spending time on "nothing".)
My suggestion:
Remodel the first part, so after Rip van fish, you go through a pipe/some kind of checkpoint and after that you have your item swimming passage. For this, even the first part might rise slightly in difficulty and then i could also approve of the whole second part as well as the last two fish-"walls" spawning so early.

In the first switch palace, you can softlock if you clip the p switch through the blocks at the very beginning of the level. I don't think that's likely to happen unless you're going super fast.

In the Dognapper, with the section with the shell going between the two on/off blocks, if you jump off the first platform a bit too early, the on/off block despawns and won't get hit, even when it seems like it should.