How do you get through Carnival Night Zone Act 2 in Sonic 3

Much of the level is pretty easy. If you're referring to the blocked off section containing only a barrel, the trick is to stand on the barrel and press UP and DOWN on the D-pad to shift the weight of the barrel, then jump off at the bottom. This has caused a large amount of frustration within the Sonic community since the game originally came out. Regarding the boss, when he drops the ball, hit him from below between the green conductors, without hitting the ball. When he makes it over to the ball, his conductors will start spinning and you need to run to avoid being pulled in. When he drops down to pick up the ball, hit him a couple of times, then repeat the pattern. The ball will never drop straight down, it'll go to the left/right and bounce a little, giving you more time to hit Robotnik/run away. After 8 hits, you've won. Or if you already have 7 Chaos Emeralds and are Super Sonic, just go straight in and hit him.