Around 1 hour 9 minutes to beat again, as shown, in this unedited playthrough. This was a game I beat on the original Sega CD many years ago and then again later, the Japanese rom, on a Sega CD emulator. Its been a while so I didnt remember the level layouts. This was me re-learning the game again unedited.
I decided to leave this playthrough unedited since I'm planning to complete the other port on Switch, Sonic Origins compilation version, at some point. I may edit that down to the successful continues since the game has unlimited continues, saves and even lets you restart on the last stage you got to, not the first stage of the Zone. I remember beating the Japanese version in about 90 minutes, so maybe that how that version worked too. Cant remember. In the original version I couldnt figure out one of the stages in the final zone, got lost, and it took me a while to beat the game. It was very easy for me the last two times I played and never got lost for very long. The first completion was probably 30 years ago though, so Ive gotten much better at games since then.