Haha, nice cover/remix you have there! Too bad you didn't remix Orr's own full version of the song, but the game version is nice enough. Plus, it loops perfectly, so that's always a good thing.
I'm guessing you remade it by ear? The subtle changes compared to the original are quite refreshing, so overall there is nothing wrong with the composition/arrangement. Even though it sounds 8-bit-ish, it isn't true 8-bit (more than two pulse waves, for example). It might be worth exploring the limitations of the original 8-bit machines, as this will give your music a more authentic feel to it.
All in all, I quite liked your piece! (Maybe that's also because I love Castle Crashers in the first place...)