Important threads worth archival are organized and discussed here.
Vroom vroom, engines.
A read-only archive of past Sonic 2 HD discussion.
Interesting highlights of General Sonic Discussion are archived here. A must read for hardcore Sonic fans.
The Knowledge Tree for hacking Sonic games.
Discussion of all Sonic the Hedgehog prototypes dumped by drx.
Topics should be prefixed by the prototype they refer to.
An archive of a former attempt at a collaborative effort to create a new Sonic game based on classic design principles from the 16-bit Sonic era.
Separate names with a comma.