@Egregor I didn't read cuppy's whole feedback post, but I decided to try your map to see what he might mean by the "visual language" comment. I'm not much one for giving feedback, but here's my thoughts:
I liked the map for the first half, but was pretty bored by the time I found the secret exit. There's decent variety in environments, but each one is barely fleshed-out. The sewers, for example; I really liked them, but I quickly got tired of seeing run-on grey brick in the following environment. The entry area is really strong, and there are some good moments like where the Phoenix Rod is. But even then, that stone cave is so bland at first. Some doomcute is even functionally copy-pasted, which makes it lose its charm. There's also some spots that are woefully cute-less, like where the Gauntlets are. Once you pick-up the items, the alcove and nearby access points are basically featureless.
There's also some questionable texture usage—purple-skull blocks with switches on them stand-out. That at least makes the switches stand-out more, which is good, but I feel like the skull blocks themselves are too basic to not look jarring. Same with the NPC's in the market-esque area: jarring.
I could go on, but I think it's best to summarize: not a bad map, but a long one, and considering how much needs done in each individual area, the map being long makes it less practical to fix everything before cuppy's projected release date.