Undertale Yellow is a very impressive fan-game! The sound, artwork, battles, and animation are all of similar quality to the original game. I also think that it struck a perfect balance of original content to reused content and characters from Undertale. That being said, I did feel like the story was a little aimless, and that the characters and humor are just not to the same degree of quality that Undertale set. The game does also take a while to get going, especially relative to its total length. It was still fun though, and I enjoyed the more difficult battle balancing.