In the Beginning of Launch Base Zone, there was (Sonic, Tails, Both: You choose)...
Go down the slope, and trip that stupid and very annoying alarm. Stay in the middle of the 2 lights, and press and hold "down", while pressing A, B, or C to make Sonic or Tails (and if you have both characters, Tails will join in the fun, too!

) do the Spin Move, and wait for the little robotic birdies fly to you and run into you while you are spinning. You will start racking up points little by little, then start getting huge points for each hit. (10,000 per birdie max!)
NOTE!!! Make sure that you:
1: Stay spinning. You don't have to keep holding the A, B, or C buttons for the Spin Move, but you do need to keep holding "down" on the D-Pad to keep doing the Spin Move.
2: Stay between the two lights. If you are not tripping the alarm, the birds will not fly at you.
3: Be Patient! To be at 100 lives, it will take you about 19 minutes and 42 seconds. This means that it will take a full life to reach 100 lives, so make that about 19 min. and 48 sec. I'm pretty good at this game, and it does not take me 100 lives to beat the game to get through this level. But I still get 100 lives by wasting 20 minutes of my time. You can never know what may happen, so plan in advance. Do get 100 lives and waste 2 lives and 20 minutes to get them. It's worth it.
4: Don't get hurt at this... It's pretty hard to lose your 3 rings, (if you got them before you got to the alarm,) by hurting yourself by colliding with the stupid barrel-rolling birds, so if you do lose your rings, I will be at my computer, playing my Emulated-version of one of the Sonic games, and I will be laughing at you.
Thanks for reading, I hope this helps, and good luck!