I've been playing the game for a while, trying different choices/paths, to get a better picture of it all. And here's my review. For those, who've not played it yet, SPOILERS AHEAD. And, without further ado, let's get to it.
We can start with the main menu. I'm not sure what "011 remake" is supposed to mean but consider changing it to "Duality". I can see a certain contrast in colors in the main menu which I think works both thematically and symbolically. Though the bright colors are dominating for some reason for which there might be some meaning but I could suggest making the main menu more balanced, with the characters in the center. Perhaps even having two sets of buttons on each side which would make it more distinct. Also, I think the characters look much better in main menu than in the game.
When it comes to the game itself, I think a custom GUI was a good idea – makes it look more solid, more professional. One of my favorite parts of the game was the limited color schemes for the backgrounds – made it look more atmospheric, maybe even a little creepy. And the changing font made it more interesting, too. But I think there are still ways the art side could be improved: more backgrounds, maybe some animation to make it all more atmospheric and lively. Also, maybe at least some silhouettes of the teachers, classmates, etc. Moreover, you can consider making separate art to distinguish oral dialogue and texting.
And, at first, I thought it was weird that there is one body but two sprites for the personalities, especially when they talk about looking in the mirror but we don't see mirror with the reflection. I suppose it can be confusing and it does make one wonder how exactly does the protagonist look (especially considering Eva says they both have the same face). But I've come to think that it doesn't really matter how the protagonist's body looks like and this two-sprite presentation actually makes it kind of cool. Also, this gives you an opportunity to eventually show how the protagonist looks like as an additional touch/twist.
The story itself is maybe somewhat niche? It deals a lot with introspection and certain psychological issues. And you could consider giving it relevant tags (e.g. "psychological"). Personally, I like psychological elements in stories and another one of my favorite parts of it was seeing the world through Eva's eyes. I could relate less to Evan and I think that's another benefit that this game has: the opportunity of having, in a way, two different protagonists. This is something you could consider emphasizing/advertising in the game's description. To make the story more exciting, it could maybe be faster-paced, could have more intrigue, more emphasis on things which are not resolved.
Moreover, this one part seemed off. The protagonist on a yellow pill when meeting Melissa for the second time. When they take the blue pill, Melissa goes "Oh, now you're quiet!" Could she have made that judgement so quickly?
I liked that there were many choices and the story could go in various directions. Having two protagonists with different outlooks and ways of handling things made it especially distinct. And I liked the options to check out things in the room without being forced to go through everything.
I also liked the music throughout. It sounded cool, distinct, matched the eerie vibes. And I liked how it would shut off for dramatic effect sometimes. Though going along with the themes of duality, you could consider giving Evan a more contrasting soundtrack along with the contrasting visuals: maybe something faster, more energetic, more upbeat. Maybe even almost jarring and harder to listen to to match his mania.
I also liked that you put some sound effects. And maybe there could be more. For example, there's a part where the door hinges "cry out" – there could be a sound for it.
And I suppose it's typical for visual novels to have a certain mismatch between the text and the visuals. For example, if a character is unlocking a door, the sprite could show them with hands in their pockets. But I personally prefer a greater match. In fact, in many cases, I think you could have easily made it work better. For example, if the character is already outside, the background could have changed already. But the changes would sometimes be "delayed" here. Also, there are other mismatches I kept noticing throughout the game. For example, I think it was Melissa's skirt that was called red but it's more like violet/purple? Another example: Evan looks nervous when telling Melissa off (not looking her in the eye, beads of sweat?). That doesn't look like him. Some sprites seemed to have been also missing. Like when Eva looks at the lamp: there's a message about something missing in the game. Also, at one part, there was supposedly a knock on the window. But it sounded more like a knock on the door (wood, not glass).
Also, I think there seemed to have been a few punctuation mistakes. For example, "No seriously". And strange spacing between words (like two spaces instead of one). For example, I think this was one part where Evan says: "THIS is MY calm." I can consider the spacing to be a stylistic choice, maybe it can be used as some emphasis of themes of fragmentation but I didn't know what to make of it here. Just looked like a mistake.
I thought it was a nice touch that the game shuts off after Eva goes to bed. It's a distinct way to end a game and I think it went well with Eva's ideas about one day being dead and the fact she's gone to sleep and, as it was mentioned, not thinking about anything when she's asleep. But it ends the same way with Evan. So you could, again, consider making a bigger contrast here: instead of a matching abrupt ending, it could be more like a slow flash of light, mimicking a limelight to go along with his dreams of being in the spotlight or maybe a vivid transition to represent his mania. It could also lead not to the window closing but to the main menu. It would parallel the different mindsets where Eva is constantly thinking about death and Evan is talking about new beginnings.
By the way, you could pay more attention to content warnings. For example, there is swearing in the game and some themes can be too heavy for some readers (suicidal thoughts, bullying, etc.).
All in all, I could tell you I liked the game. It had many cool things but there are always many ways something can be improved. I hope you find my review encouraging and constructive. And I wish you good luck developing it further.