Choose the HELP menu, then select ABOUT. Hold Shift and click on Bug's pupil. A white box will appear. Type "babyseals", then click on WOW. A new blank menu will appear next to the HELP menu. This menu includes level select, invincibility and more!

Activate the Cheat Menu, then select the Flying Bug option. To use it, press and hold Y while playing.

Activate the Cheat Menu. To skip to the next level while playing, hold the Duck button and press Up.

Hold the Duck button and press DOWN to return to the previous level. If you are already on the first level you will be sent to the bonus level.

Go to Reptilia. Use the flying bug cheat and fly around until you find rocks made into the shape of the word GO. Go to the very beginning of the word and there should be a track in front of it with Sonic standing on it.