It has its moments for sure. I'm fond of the Pokémon formula, even though I have a lot of criticisms of it. This game certainly tries to forge its own path, but it is very Pokémon, and falls into a lot of the same traps as Pokémon.

I'm personally not fond of the open-world format. Pokémon Scarlet and Violet's structure was much the same, but I'm much more fond of the Metroidvania-lite thing the first few gens had going on.

As a game made by Pokémon fans for Pokémon fans, I'm sure a lot of people will really get a kick out of it. But as a game made from scratch with Pokémon in mind, I would've made a very different game and I couldn't shake that feeling as I played.

Undertale Yellow is a game I have many thoughts on.

First, as a fan project, it's phenomenal. Probably the best I've ever experienced. Almost everything I loved about Undertale is represented, while it manages (in my opinion) successfully to forge its own identity through original characters and scenarios. It's funny, it's heartwarming, it's heartbreaking, it's precisely what you would expect out of a competent fan-made follow up to Undertale and does not disappoint. Several aspects of the game exceed the original Undertale, and that's not something I regularly get to say about fan works. I feel bad about the fact that I, and everyone else, had to play this game for free, because this game very evidently took a comparable amount of work to the actual original Undertale, and the devs really deserve that credit.

Second, as a follow up to Undertale. It's a bit unfair to judge a fan work like this as if it was a legitimate follow-up, but it's hard not to do so when considering the absolute quality of this project. "Fan game" and "Fan fiction" can easily be dismissed as lesser compared to original work, I'm guilty of this myself, but I think this game deserves more than that. This is a real game. And, continuing with that in mind, I have thoughts.

Undertale Yellow is derivative to a fault. This is, of course, a weird criticism for a fan-game, but it remains true. Throughout my experience I couldn't help but think "we've done this before". It has a lot of the same emotional beats as Undertale, it has roughly the same game structure as Undertale, it doesn't have anything fundamentally new to offer, in the way that I believe the actual official Undertale follow-up (Deltarune) does. This, of course, is by design, at least to some extent, if not entirely, and maybe that makes it kind of a hollow criticism. "Why did you go into a fan game expecting something new". And to tell you the truth, I didn't. But, as I was pulled into the Underground again by this, and I cannot stress this enough, magnificent experience, I couldn't help but feel like it was a real, legitimate sequel. It's just that good. And so, it sits in a bit of a weird grey area. The creators set out to create "Undertale", even though that game already exists, and they succeeded. The fact I even feel the need to compare it to the official Undertale follow-up is an achievement.

That peculiar, self contradictory status of the game aside, it's wonderful. I'm very happy I got to play it and huge shoutouts to the team behind it, you guys made a legit game and you should be proud. You stand among the legends of fan-game history.
👍👍👍