Act 3 is another short run to the boss. The level itself is relatively simple, focusing on a few platforming challenges before you reach Dr. Robotnik. Collect as many rings as you can before entering the boss arena. There are usually a few ring monitors and a shield monitor available.
Boss: Egg Mobile (Flamethrower). Dr. Robotnik will appear in his Egg Mobile, which is equipped with a flamethrower. He will fly back and forth across the top of the screen, occasionally descending to shoot flames downwards. The arena has three platforms that rise and fall into the lava. To hit Robotnik, you need to jump from one of these platforms when he is low enough. The challenge is timing your jumps to avoid the flames and the rising lava. Hit him eight times. After each hit, he will speed up or change his pattern slightly. The key is to stay on the highest available platform and jump when he is directly above you and vulnerable. Be patient and don't rush, as falling into the lava is instant death.