I have never seen another Undertale fanwork that so intimately understands what made the original work so well. This could easily have been a low-effort nostalgia-trip, but the sheer dedication to making this project a worthy successor to Undertale's cannot be overstated. Everything from the sprite quality to the music to the boss mechanics go so above and beyond what was required of them, to the point where I would almost believe this was a Toby Fox creation if I knew nothing about it beforehand.

Undertale Yellow spends a lot more time with its characters than the original, tending to have them stick around even after finishing their area rather than just disappearing into the background. You really are given so much more time to understand their personalities, and characters like Martlett and North Star are just as full of life and charm as any of the characters in the original game. This game is so overflowing with charm and personality that it barely even knows where to put it all.

The game also looks gorgeous, with more detailed backgrounds and far more sprite animation than the original had. Importantly, though, it doesn't look too good. A problem I have with a lot of undertale fanworks is that they don't understand that Undertale kind of needs to have a low-budget, homemade charm to it to maintain its atmosphere. All the dumb sprite inconsistencies in the original game are so near and dear to my heart, and Undertale Yellow captures that same aesthetic while still being noticeably easier on the eyes.

One thing I have to give this game immense credit for is using almost zero established characters or map layouts from Undertale. It would have been so easy for Clover to bump into the same cast of characters that Frisk ran into back in 2015, but the developer shows a shocking level of restraint in how they approach this established world. Focusing on new parts of the Underground makes it feel so much more like a real place, and the worldbuilding is such a natural extension of everything we already know about the place. While it does bear the Undertale name and world, it focuses so much of itself on new, original content, that it feels almost entirely new.

I don't want to get into heavy spoilers here, but I also appreciate that this game isn't going for the same sense of spectacle that the later encounters in Undertale do. It's a much more personal story, which makes sense considering breaking the Barrier is never in question at this point in time. While I do find the endings slightly less impactful because of this, they're aiming for such a different kind of emotional response that they mostly succeed in.

This review might be long and rambly, but I just finished the game and had so many thoughts I had to put down. I adore Undertale Yellow. It means so much to me that a group of fans were able to so distinctly understand what made Undertale great and use that to make something almost completely new within its world. I cannot recommend it more as both a companion piece to the original, and a fantastic indie RPG in its own right.