Manage to beat a stage at with your time at exactly 9:59 and you'll net yourself an easy 100000 points.
To do this, you must have a copy of Sonic the Hedgehog 2. activate sonic 2's level select (sound test: 19, 65, 9, 17)
Now, without turning the system off, remove the cartidge, and insert the Sonic 3 Cartridge. Reset the Genesis console, keeping the A button held down at all times. On the title screen, press down untill you see sound test.
Success! you now have an easy (but different) way to access the level select and sound test!
If you are afrade of this damaging your games, please, don't try it. I have never had any game be damaged by this trick.
BONUS: If you look at the level Icons, you will see the icons from sonic 2. If you look carefully, you will see the Icon for Hidden Palace Zone, a level that was "removed" from Sonic 2!
When playing a level after enabling the level select cheat, pause the game, then press the C button to advance the game by one frame.
On the level select menu, play sounds 01, 03, 05, 07. Highlight Special Stage 2 and press A + Start.
Get up to Launch Base Zone. Sound any of the alarms, so that the Kamikaze birds come after you. Charge up a Super Sonic Dash in between the alarm, but do not let go of the button. The birds will continually crash into you. After about 30 seconds, you will have gained enough points to get an extra life. Continue the process for as many lives as you want.