I'm not familiar with Haru Mizuki at all, so I'm definitely not what this game is for. As a VN, the writing is probably about as verbose as can be expected, but as a game with gameplay I do wish it could be trimmed down a little. For a fan game, I guess the story doesn't really need to make all that much sense as long as you're appealing to your target audience of other fans, so even if it's cliched or nonsensical I think that's fine as long as you stay somewhat consistent with it.
That being said, I couldn't really come up with any specific traits about Haru's character from the game itself. So far, I don't feel like you've really been able to capture the personality or branding of your VTuber; the character seems rather generic in how he's reacting to things and what he does. Maybe feeding him is something relevant to his character, but that's about it. Perhaps it's just that as a smaller VTuber, he doesn't have the same level of branding as some of the bigger ones out there, but I'm sure there's some more inside jokes and references you can put into the story for other fans to enjoy.
I got stuck off-screen in the maze part and couldn't continue; seems like I managed to enter the screen below where the bottom tree line is? This was after I went up into the wrong part and got sent back to the start, right at the top of the first room, and immediately walked up back to the axe room because I was holding down the up key.