The game has a great potencial but i felt that everything was rushed, you could put more time in every character so the player care about them. I didn't have enough time to care about the characters specially Ai, because her dialogues were a bit overdramatic, you could tone down things a bit and go levelling up as the game progresses. Both endings were good, but because i didn't care enough about none about Ai, the protagonist or Emily why should I bother, besides that Ai's ending surprised and Emily's one was predictable but good enough.
About the protagonist. He isn't a good character, he is childish, overdramatic at some points and isn't relatable for me at least, he blames everybody else for his defects and problems besides it all being his own fault. You could make him recognize his flaws and try to become better, but failing, that would make easier for the player to care about him and his relantionship with Emily because he would want to be different but he can't so we may fell bad for him and try to take the best choices for him.
You could use the fact that it's a game inside a game to make something more interesting, like making the player put his name in the game and create another name when the protagonist starts sweet crush so when Ai gets out of sweet crush there could be a dialogue were she realizes that the person she was obsessed with wasn't real than making her have some form of existencial crisis or to try to speak with the player or something like that. Maybe making she mess with the sound and the graphics trying to connect directly with our world or messing with newgrounds site if there were a fullscreen version, like creating the illusion that the game got out of the fullscreen version by itself and opening other sites I don't know, just saying some ideias you could add to this game or future ones.