Senbei sucks. He's very funny, I like him. Manjuu also sucks. I don't like her as much, but the whole situation is very entertaining. Then Osmanthus route's "True end???!?!" had me dying. I enjoyed the comedy overall, I'm glad April Fools' is every year.
Also, because I needed a refresh (my memory's bad) I checked your character gallery and I must say I really appreciate the characters commenting like it's social media. Senbei going "why is this entry up? Someone should contact the developer" and having downvotes was hilarious.
If you don't have enough time to make music for this, I'd at least add sounds for cursor and selection (?). I think it's good as it is, without music.