I own SMB3 for NES, the bar on the left side is there, and the pixels you are talking about that move are actually required by the game to keep IRQ counters working. A recent ROM hack removed them and it blew up half of the game, but even when fixing it all, once you got to the final Bowser fight, things were corrupted because it didn't have it. Also, as you progress through the screens the palletes are messed up on the next line for a second, just like the original. When you make an emulator, it has to emulate the NES, not the game. That's why all of this shows up on VC also, and Nintendo couldn't simply edit the emulator to change that as it would blow up things and not work for other games that may rely on things. For instance, randomness in games is based on RAM checks, if they edited the emulator and fixed bugs and whatnot, it would make the games random checks different and then it wouldn't be faithful to the original game.