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Marble Zone is the best zone in Sonic 1
(imgur.com)
Tabletop, DnD, board games, and minecraft. Also Animal Crossing.
3rd International Volunteer Brigade (Hexbear gaming discord)
Rules
The whitehead remaster's inclusion of spin dash and elemental shields gives you enough extra tools to make this a pretty fun zone to navigate.
The 1991 version, though... well, I don't want to break rule #3. I will just suggest that there is an overly high skill floor to navigating Marble Zone quickly.