[Sonic 3, Normal or Easy] While you no longer need to get past the barrel of doom, an extra life might be hiding as a reward for dealing with one underwater
[Sonic 3, Easy] A Ribot and some spikes are missing somewhere in Launch Base Zone act 2 and has been replaced with a boost pad. Use the boost pad to trigger
[S3&K, Normal] As Sonic (without Tails), obtain a Fire Shield in act 1 of Angel Island Zone and clear act 2 without losing it (no special/bonus stages)
[S3&K, Normal] Reach the boss of Hydrocity Zone act 1 without going in the water as Knuckles without dying, using super/hyper, or going into special/bonus stages
[S3&K, Normal] As Tails, successfully fly from the first outside platforming section to the start of the next outside section by going under the level in act 1 of Flying Battery Zone
[S&K, Easy] It's no fun having your speed stopped by something grabbing you. Launch yourself from a spring to where you would normally be caught by one of these in Mushroom Hill Zone act 1 (Level Select allowed)
[S&K, Normal] As Sonic, beat the boss of Flying Battery Zone act 1 without getting hit, pressing left or right, or using Super Sonic (Level Select allowed)
[S&K, Easy] Remember all those spinning pillars in Flying Battery act 2? Find the one that no longer has any platforms to crush you (Level Select allowed)
[S&K, Easy] A set of fifteen rings and a 1-up has somehow become harder to reach, so put your spindash jump and electric shield skills to the test (Level Select allowed)
[S&K, Easy] Not only has a crumbling platform section been changed, some clouds were added as well! Use them to skip where the first boss is (Level Select allowed)
[S&K, Easy] Who needs those long platforms that angle based on your position? Let's have rising stairs instead! Land on one of the sets of platforms with a spring (Level Select allowed)