As a gamer who's not big into Sonic aside from the Adventure titles, why is this a big deal? Didn't Sega do this with the episodic content and it failed miserably? How is this different?
Sonic 4 used ugly pre-rendered visuals, physics that were not only not faithful to the Genesis games at all, but just completely busted all around, and was farmed out to a developer that's mostly put out middling handheld Sonic titles, the best of which have a completely different design philosophy from the Genesis games.
Sonic Mania's being built by the people responsible for the excellent mobile ports of Sonic 1, 2 and CD (The latter of which also got a fantastic HD port), uses faithful looking 2D spritework, and is pretty much being designed by people that have pretty much disassembled the original Genesis games back to front. They're probably the best possible people to have making this short of reassembling the original development team for the Genesis titles. (Which is never happening.)
Well yeah, but they weren't new level designs and mechanics and bosses. They were already good Sonic games just remade/ported/put on a new engine. I'm just worried that it will have the look and feel of a classic game but bad level designs and bosses like the Sonic 4 games, the last attempt at 2D Sonic.
Hidden Palace in Sonic 2 mobile was actually mostly original level design outside of the first area of the level. Had a new boss fight, too. Was a generally inoffensive level from a design standpoint, all things considered.