SNES favorite Super Mario World has become one of the most popular titles for ROM hacking, which is no surprise since fanatical players have gotten so good at the original that they've managed to beat it blindfolded and without using their limbs. RELATED: Best Video Game Console Launch Titles

These fan-made games are generally available for free online, giving those who've mastered the classics a chance to try a wealth of creative sequels. Popular titles that left gamers hungry for more levels and more complex challenges led to the proliferation of ROM hacks, where industrious individuals modify game elements like graphics, level design, and music to create something entirely new. Sometimes, the only thing wrong with a game is that there just isn't enough of it.