World 3 Boss Glitch

[RandomBagel]

I recently bought Super Meat Boy, and I'm really enjoying it so far, but there is a glitch that makes it impossible to get past World 3. Brownie is way slower than he should be, and the cutscene doesn't trigger when I get to the end. The salt just disappears, and if I wait long enough, Brownie gets to the end and freezes in mid-air. I'm really enjoying this game and I don't want a glitch to ruin it, so please tell me how I can prevent this from happening.