Sonic 3

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!

Enter Debug mode, start a level that has a special stage ring, choose a sprite of your choice, enter the ring as that sprite and hit B twice, as soon as you leave that zone, you'll be that sprite for the rest of the level.

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.

When the "SEGA" screen fades, quickly press Up-up-down-down-up-up-up-up. If you have done this right, you should be able to scroll down to "Sound Test" below "Competition". The ups and downs are very difficult in the short amount of time provided, but with practice, it is pretty easy.

Start a game and go to Angel Island Zone Act 1. Go to one of the swings that you hang from and grab on. While Sonic is swinging, press Left, Left, Left, Right, Right, Right, Up, Up, Up. You will hear a ring if you entered the code correctly. Pause the game and press A to take you back to the title screen. Press Down twice to find the newly unlocked Sound Test menu. Enter it, where you can play all of the sounds/music in the game and warp to any level.

When you have done the level select cheat go to the Stage Select screen and choose the special zone for playing Blue Sphere. Select Knuckles as your character and start, when you quit and go back to Stage Select and choose a stage, you'll be Knuckles without having to use the Sonic and Knuckles add on.

When playing any level which you have accesed using the cheat menu , pause the game and hold down B. Whilst B is held down , the game will play in slow motion mode.