Thanks again for testing my level. It's funny a lot of what you mention is exactly my thoughts during the creation phase. Verticality was one of my first thoughts about replicating World 7 which is why I tried to recreate it in the sub world. For me I remember Pipe world for its puzzles. Some of what you said made me chuckle. The top run with the coins, I flirted with the idea of cutting it off after the coins but chose not to. Maybe that was the asshole in me haha. There are hidden blocks against the left pipes in the water so you should always be able to get out but if I've missed some let me know which section so I can amend. Lastly the hint about the exit pipe....you hit the nail on the head, the original designers by that point were hardcore so I took a conscious decision to leave as is. My hope is when people see my levels they'll start at the first one and then see the increase in difficulty though I appreciate when it is in versus and coop they wont have that option. That bit I dont have any regrets I'd love to see the mad scramble in vs trying to find it!
Lastly about aesthetics, again we're like minded. I dont like that some of the sub world looks out of centre but I wanted so many different sub world sections I had to divide the screen up resulting in issues like that. I'm a perfectionist and I didn't like it either haha. Last on my list is a homage to Dark World!