This hack isn't exactly the most fair instance of a "hard" hack I've seen. Most of the trouble I had getting through it was because of the disproportionate saturation of enemies compared to the amount of midway points and powerups.
Not only that, but in 'Cement Town' it's nearly impossible to tell what's a wall and what's not, since the only difference between pass-through blocks and solid blocks is a difference in Y-flipping. While with the backwards question blocks it's a bit more obvious because they're animated, the entire level is made out of cement blocks.
Speaking of the backwards question blocks, it's a rather dumb gimmick. If you've built up the reflex where if it looks like a question block you hit it, then it will punish you for that for no apparent reason.