After finishing all possible routes, I have to say it's a really cool fangame, but it's in a superposition of also being just a really alright fangame and maybe an okay video game. Incredibly minor non-spoiler systematic spoilers ahead.
I will stay my hand from making a huge overanalysis because it's been a while since I've really played and beaten a game, but to boot, there's a lot this game does right. The game system is fully faithful to Undertale, and there is a lot going on that made this game feel entirely official. I saw a startup for this game back in 2016 and didn't think it would actually get anything but abandoned as fangames tend to go, but I like the result. There are also some wonderful additions and QoL that I could go through, like big battles having MOTHER-inspired backgrounds (lovely!) - but my favourite personal thing is how there's a new effect upon sparing a major enemy - a wonderful piping sound effect with the box borders glowing yellow. It is simply a wonderful addition and I can't get enough of it, but sadly it is underutilized and I was hoping later on that there would be moments where the effect would sink in and hit different especially after some struggle.
But that's where the nitpicks come in. Essentially, a lot of these major encounters feel weak. On a usual playthrough, to spare these characters usually require just stalling out the game instead of using the Act mechanic, and a few of these battles also end automatically without the spare button. Alongside that, a lot of these characters end up never appearing again, such as the very first one despite some story implications that would make him a stand-in Toriel. I get confused at some of the other ones who do quite the same or feel like they don't have an outstanding part to play. I love the dance fight boss but he just always fades to nothing after the fact.
Part of this must be due to how short the game and story is in comparison to Undertale, in which I have to give it leeway for that reason. But unfortunately, the usage of time and resources have left myself and some other players with a lot to be desired. When it comes to variation in the Neutral and No Mercy routes, there isn't too much of it in the story, so if you abort a Genocide run, you're really only doing it to see how characters react in the very current scene - if it's the other end around, the deaths of some characters seem really inconsequential. It's not something to do a full run over. There's little in the way of re-doing sections too, as cutscenes don't get mildly changed as they do in Undertale, and route changes only affect the heat of the moment. But another thing is that No Mercy should be very emotionally powerful for the other characters, but some incredibly sad missed opportunities passed us and characters that would become more interesting or fun in that route end up being sidelined, partially because it brings us to the next big problem...
Ceroba. She is a character that has a presence upon all the routes, and a bit too much so - while Undyne in Undertale was a prominent boss in all the routes, she didn't do so as a behest to other characters. She was fought within the zone she was introduced in and later was seen again later when it was called for and the player's exploration. Ceroba is a character that doesn't belong to any particular "zone" in Yellow, is introduced early, and basically takes up the entirety of the game's plot and gameplay starting from the halfway point (if we consider all routes put together, with a mix of it if individually speaking [in which in No Mercy, my qualms are with her receiving a fight instead of another character even if it would be tough to rationalize it]). In pacifist, the player soon realizes this entire game is pretty much about her backstory, sidelining most of the other characters and finally having so much more exposure and resources dedicated to her (well, I'm not sure it's a contest with the other routes' final bosses, but let's just say pacifist felt the longest and slowest). Ceroba tended to slow down the story quite a bit, partially due to the Steamworks area feeling slow and breaking the pacing on its own. On an aside note, the Dunes area also felt like one big slog, especially on replays with the mining area. I don't know what it exactly accomplished when you don't meet anyone. Ceroba also really broke my immersion for me, considering she is a kitsune miko with her story arc and everything else really going hard with the Japanese theming when the rest of the game rides strongly on the Wild West flair. In complete honesty, she feels like an OC that was made before, not for Yellow, and shoehorned in by a creator that really really liked her and just wanted to present her story in an Undertale setting, similar to the early days of people putting their OCs in Unitale. I'm not alone in feeling that she gives several signs of this favouritism - because either way, she takes up like a third of the screen time and it doesn't leave the other already-barren characters with much. Her characterization also is hard for me to like, and I feel like the game is trying to make you sympathize over an incredibly selfish character as time goes on, making her plight seem worthless. The "gunfight" fight was the one I was expecting to be the best in the game, but it sadly didn't amount to much - I thought it was weak. Which is sad because Starlo in retrospect is a bit of a butthead and kind of gets casually excused for it, in which we don't actually SEE him redeem anything. Given this game had a reference to RED, I was hoping some pointers would have been taken on having a point to some fights.
Which is why I can't say much about the remaining major characters. I do like them in general. Quite a few of them seem to be something that could be an official character. I positively enjoy a select few. There were some narration punchlines and puns that made me laugh out loud. But some of the writing in this game seems to get quite a bit quirky and based off overly-online interactions that took me really out of the immersion of the Underground's setting. More often than not, this kind of thing was something that Undertale reserved for only a few cases, and even then, it was something mundane like anime which the monsters could very well know given the rest of their technology. Sadly, Yellow was enough to make me cringe at least twice with examples that I will pass on. Aside from that, I'm mixed on one character because she is very Papyrus-like in role but with fifty layers of uncertainty. I think she could've been more interesting, but her fights at least really made up for it to me. Another thing that I find is that I feel like there's less intent on making the NPCs more monstrous and creative and gave a lot more characters more animal designs but this could be a moot point as I don't remember a lot of Undertale NPCs by face so ignore me.
If it wasn't clear, my major problems with the game was the story and characterization, and I do kinda wish we got to a real final Asgore fight even if it was hopeless, but all this aside, I do not dislike the game, I just think it is flawed. The music is really good - not as good as Undertale's, and I personally think some of the endgame battle themes are quite underwhelming and all over the place in composition, but it is still good and there are some themes I wouldn't mind listening to on loop. Many of the monsters are designed wonderfully, attack patterns are fun (I didn't have a problem with the endgame ones everyone has been complaining about cuz uhh touhou), animated sequences are really nice, and I have to commend the efforts made nonetheless as reusing assets and music was done as little as possible in comparison to all the original content this game has. And it's a free fangame, of course. But I really do wish the story wasn't compromised some bit.
I did say I wouldn't overanalyze it but it's more like I just said a bit too much on my main complaints - I'm sure someone more attentive and hardcore than me could rip the issues to shreds and rate the plausibility of the story compared to Undertale and yadda yadda, but I do recommend this game to anyone who's beat Undertale. Yellow simply isn't the best thing ever, and while I applaud its efforts lots, it couldn't avoid characterization pitfalls and I am simply disappointed of whoever blindly says it is better than the original.
I will stay my hand from making a huge overanalysis because it's been a while since I've really played and beaten a game, but to boot, there's a lot this game does right. The game system is fully faithful to Undertale, and there is a lot going on that made this game feel entirely official. I saw a startup for this game back in 2016 and didn't think it would actually get anything but abandoned as fangames tend to go, but I like the result. There are also some wonderful additions and QoL that I could go through, like big battles having MOTHER-inspired backgrounds (lovely!) - but my favourite personal thing is how there's a new effect upon sparing a major enemy - a wonderful piping sound effect with the box borders glowing yellow. It is simply a wonderful addition and I can't get enough of it, but sadly it is underutilized and I was hoping later on that there would be moments where the effect would sink in and hit different especially after some struggle.
But that's where the nitpicks come in. Essentially, a lot of these major encounters feel weak. On a usual playthrough, to spare these characters usually require just stalling out the game instead of using the Act mechanic, and a few of these battles also end automatically without the spare button. Alongside that, a lot of these characters end up never appearing again, such as the very first one despite some story implications that would make him a stand-in Toriel. I get confused at some of the other ones who do quite the same or feel like they don't have an outstanding part to play. I love the dance fight boss but he just always fades to nothing after the fact.
Part of this must be due to how short the game and story is in comparison to Undertale, in which I have to give it leeway for that reason. But unfortunately, the usage of time and resources have left myself and some other players with a lot to be desired. When it comes to variation in the Neutral and No Mercy routes, there isn't too much of it in the story, so if you abort a Genocide run, you're really only doing it to see how characters react in the very current scene - if it's the other end around, the deaths of some characters seem really inconsequential. It's not something to do a full run over. There's little in the way of re-doing sections too, as cutscenes don't get mildly changed as they do in Undertale, and route changes only affect the heat of the moment. But another thing is that No Mercy should be very emotionally powerful for the other characters, but some incredibly sad missed opportunities passed us and characters that would become more interesting or fun in that route end up being sidelined, partially because it brings us to the next big problem...
Ceroba. She is a character that has a presence upon all the routes, and a bit too much so - while Undyne in Undertale was a prominent boss in all the routes, she didn't do so as a behest to other characters. She was fought within the zone she was introduced in and later was seen again later when it was called for and the player's exploration. Ceroba is a character that doesn't belong to any particular "zone" in Yellow, is introduced early, and basically takes up the entirety of the game's plot and gameplay starting from the halfway point (if we consider all routes put together, with a mix of it if individually speaking [in which in No Mercy, my qualms are with her receiving a fight instead of another character even if it would be tough to rationalize it]). In pacifist, the player soon realizes this entire game is pretty much about her backstory, sidelining most of the other characters and finally having so much more exposure and resources dedicated to her (well, I'm not sure it's a contest with the other routes' final bosses, but let's just say pacifist felt the longest and slowest). Ceroba tended to slow down the story quite a bit, partially due to the Steamworks area feeling slow and breaking the pacing on its own. On an aside note, the Dunes area also felt like one big slog, especially on replays with the mining area. I don't know what it exactly accomplished when you don't meet anyone. Ceroba also really broke my immersion for me, considering she is a kitsune miko with her story arc and everything else really going hard with the Japanese theming when the rest of the game rides strongly on the Wild West flair. In complete honesty, she feels like an OC that was made before, not for Yellow, and shoehorned in by a creator that really really liked her and just wanted to present her story in an Undertale setting, similar to the early days of people putting their OCs in Unitale. I'm not alone in feeling that she gives several signs of this favouritism - because either way, she takes up like a third of the screen time and it doesn't leave the other already-barren characters with much. Her characterization also is hard for me to like, and I feel like the game is trying to make you sympathize over an incredibly selfish character as time goes on, making her plight seem worthless. The "gunfight" fight was the one I was expecting to be the best in the game, but it sadly didn't amount to much - I thought it was weak. Which is sad because Starlo in retrospect is a bit of a butthead and kind of gets casually excused for it, in which we don't actually SEE him redeem anything. Given this game had a reference to RED, I was hoping some pointers would have been taken on having a point to some fights.
Which is why I can't say much about the remaining major characters. I do like them in general. Quite a few of them seem to be something that could be an official character. I positively enjoy a select few. There were some narration punchlines and puns that made me laugh out loud. But some of the writing in this game seems to get quite a bit quirky and based off overly-online interactions that took me really out of the immersion of the Underground's setting. More often than not, this kind of thing was something that Undertale reserved for only a few cases, and even then, it was something mundane like anime which the monsters could very well know given the rest of their technology. Sadly, Yellow was enough to make me cringe at least twice with examples that I will pass on. Aside from that, I'm mixed on one character because she is very Papyrus-like in role but with fifty layers of uncertainty. I think she could've been more interesting, but her fights at least really made up for it to me. Another thing that I find is that I feel like there's less intent on making the NPCs more monstrous and creative and gave a lot more characters more animal designs but this could be a moot point as I don't remember a lot of Undertale NPCs by face so ignore me.
If it wasn't clear, my major problems with the game was the story and characterization, and I do kinda wish we got to a real final Asgore fight even if it was hopeless, but all this aside, I do not dislike the game, I just think it is flawed. The music is really good - not as good as Undertale's, and I personally think some of the endgame battle themes are quite underwhelming and all over the place in composition, but it is still good and there are some themes I wouldn't mind listening to on loop. Many of the monsters are designed wonderfully, attack patterns are fun (I didn't have a problem with the endgame ones everyone has been complaining about cuz uhh touhou), animated sequences are really nice, and I have to commend the efforts made nonetheless as reusing assets and music was done as little as possible in comparison to all the original content this game has. And it's a free fangame, of course. But I really do wish the story wasn't compromised some bit.
I did say I wouldn't overanalyze it but it's more like I just said a bit too much on my main complaints - I'm sure someone more attentive and hardcore than me could rip the issues to shreds and rate the plausibility of the story compared to Undertale and yadda yadda, but I do recommend this game to anyone who's beat Undertale. Yellow simply isn't the best thing ever, and while I applaud its efforts lots, it couldn't avoid characterization pitfalls and I am simply disappointed of whoever blindly says it is better than the original.