Well I just gave this a shot. It still chugged a bit on my machine, but for the most part it was much better. I tried the puzzle path for the first time and got lost a couple of times.
First time in the icicle room, when I'd finally made it to the top I saw a brown bustable block right in front of me and immediately assumed it was the path forward. I then had to backtrack all the way up there and didn't notice the ice block until the second time around.
The second time in the icicle room, I'd noticed those frozen water fountains earlier and figured they were important. Once I got up to the top I saw one in front of me leading to a hole in the wall.
Unfortunately, I messed up trying to thok to the fountain so I jumped out of the melted lake and tried again and again. Then I tried going from the bottom fountains and working my way up. At one point an unlucky framerate drop combined with bad reflexes sent me into a pit while trying to make my way back to the top.
After starting all over, I finally made it to the hole in the wall on the other side only to find out it was a dead end with nothing but a 1up for my trouble. Confused I jumped back down into the melted lake and then accidentally found the way forward.
Lastly, the infinite loop was interesting but I'd gone in and out of the same two dead ends over and over. In the end it turned out that a very solid looking blue wall wasn't quite so solid. It didn't quite make sense.
The first problem is a result of the brown bustable block being far more obvious than the ice block you're supposed to break. The second problem was because you can't see the way forward easily. The third, well I'm not sure I understood it well enough to know what happened.
Besides these things though... as a whole, I've come to the conclusion that I'm just not skilled enough at SRB2 to play this kind of map. Most of my other issues were nonsense stuff that I doubt would be a problem for anyone else.