First of all, I liked the game. The puzzles are well designed despite their simplicity. I like for one the reuse of existing switches and mechanics that have previously been used to get to an answer for a second time. This makes them less of a filler within the game. My compliments on that. I can also laugh at the way some hints are given. In a lot of cases though, rather than a hint, you're given straight up an answer. Though there is a mystery about where to use it I guess, which works fine. It makes the game a bit on the easier side which is fine and works well. The game in question can be enjoyed simply for its mechanics and puzzling alone, which is great.

I'll try to add points to other existing reviews that people may skip out on with my own. These are things I find questionable:

In my opinion, YonYon-san's biggest mistake in this game is the number of ending variations. The game was originally uploaded to Nico Nico Douga's Game Atsumaru service. This means that the game was intended for online, in browser play. The only way you could officially see each artwork YonYon made using Waifu Diffusion was by completing the requirements needed and for a number of them that means grinding Ending 2 using different conditions. This takes up a lot of time to achieve for a player and considering the text, lore and flow involved remains the same for almost all of these, its quite a lot to go through. If the player for whatever reason cleared their browser history, the endings unlocked earlier could no longer be viewed as well.

My advise for other developers and for YonYon here would be to 'limit' the amount of images you generate with stable diffusion as to not make this mistake, or by making the unlock and view  requirements less strict if you intent to publish the game as a 'web app' online. Keep in mind that this isn't as much of an issue if you make the game 'offline playable', since you garantee save files and the player can just play whenever they want. The requirements to unlock the GC and view them, as can be seen in this game, can easily end up adding hours of repeated exposure to the same content in game for the player.

The second issue I want to address, which is similar in nature is the way the mimic is programmed. You're required to fight it each time you leave the room in case you wish to interact with it or when you wish to use a different code. You can't just type in the passcode to claim the content even if you know it up front. This causes a ton of unnessecary repeated battles. Also, another thing to mention here is that the Guard option, if used, doesn't give any answer leading to a reward, despite the codes they create being valid. In all cases the chest ends up empty when inserting a code revealed when using guard no matter which combination of circumstances. Thanks to Guard, the amount of possible passcodes you can guess through is doubled and it is unfortunate that the result is always the same.

A third thing I can see problems with is the use of French. Though the stereotype in game alone makes me facepalm, the primary issue is that not everyone knows French, and it doesn't work too well when the developer or translator explains Senpai and Kouhai, but not Merci. It's inconsistent there. Also lore-wise, it makes little sense to use French in game. Especially after the transformation made the character understand what it means instead of 'seeing it as squares', French could be completely omitted. Speaking of squares, I noticed that the same French doesn't appear in text that isn't spoken by a character, despite the lore hinting it would be in French. There are two other problems I see with French in the lore. Gothic Lolita fashion originated from Japan. I assume the association with French comes from the MMM brand, but again, its Japanese. The use of French is only in the brand name. Gothic Lolita fashion is based on Victorian Goth, which means its based on the British Fashion from the Victorian Era. The second thing is that it was about an exchange student and them speaking to a someone originating from Japan within Japan. They're not in France. (I have seen a couple of other RPG Maker projects pull French out suddenly, or just speak in kanji and kana all of the sudden to give them a personality, but the same translation issue will happen there; people can't read that.)

Other than that, like I said its an okay game.

The transformation system is cool. I like the way they implemented it at least. The endings are a bit too much in my opinion, on the transformation scale. It seems to come out of nowhere in some. Also the ramna-half references.

In the end: I think more could be done with this idea even in the same setting. There is for one a set of valid, but apparently unused passcodes. Rather than completely separating the two characters, they could be interacting with eachother at some point. Things like that. The game ended up being short with room that could be filled.