One of the fastest speed-runs of the first Sonic game out there. Yes, it is tool-assisted, as it's obscenely hard to speed-run the entire game in one shot. However, there are plenty of unassisted Sonic speed runs out there of individual levels that do pull off many of the times seen in this video. So as a proof-of-concept, this speed run is more than sufficient.
My favorite parts are Act 3 of the Green Hill Zone, and the entire Starlight Zone.