Basically, ZSNES, the emulator that the RGR Plugin uses, has a giant emulation flaw in the level Kremlin Karnage.
There's a barrel with a spinning arrow on it, that is supposed to only rotate at the player's will, but instead of doing so, it constantly spins in the same direction making the level mind-numbingly hard without the assist of save states or the like (shame on you!).
There are more of these barrels scattered throughout the game, but those don't hinder the gameplay as much as this one, as a big chunk of the level revolves around it.

A buddy of mine (Kieran Menor) was livestreaming his play-through of the game recently (he's actually still at it while I'm posting it) and when he encountered this emulation flaw, he quickly figured out a "Cheat" to fix that error, making the level enjoyable even on ZSNES again.

I'm not sure if it's possible for members to add cheats to the cheats section, but I didn't see a button or anything, so I'm posting this here;
To bypass the emulation flaw (if you're using the RGR Plugin and not the other emulator), simply hit Escape, enter the Cheats menu and add these two codes and toggle them on:

7E0E0B00     DIDDY BARRELFIX
7E0E6900     DIXIE BARRELFIX


After you did that, just continue playing the level and the barrel will work just as intended, but I'd recommend switching it off after the level has ended, since we're not sure how the cheat affects the other barrels in the game.