Suggestions :) X0
You should add the feature to fuck Mizuki when you realize she's doing something to you in your bed .
Add a feature to drink water before bed so when she tries to bj you'd shoot pee and insert ahegao.
More possible ways you could fuck Mizuki while laying in her bed, like oral sex, anal and diff normal sex positions.
Add a detour option for the town trip event where you could have sex in a bust stop or the park or the pond.
More locations:
like a kitchen where you could interact with grand mother whilst eating in the dining table and Mizuki can either Footj you or bj under the table.
The well, or the barn where you could fuck Mizuki and avoid to get caught by your grandmother.
Alley ways and isles in the store and store are where you could do public sex.
More minigames too, like minigames in every room each that leads to an intimate scene :
Like a rock paper scissors game in the bathroom to pick who should wash each other's backs and you can touch her if you win and she'll touch you if you lose.
Pillow fight in your bed, where you need to dodge pillows using arrow keys where you could pin her down at your bed after you win or Mizuki could dry hump the pillow when you lose.
Fast clicking games by the garden to kill insects and if you lose Mizuki will get swarmed by insects and you need to help her accidentally groping her and if you win it could initiate the garden walk event.
Sorry but my imagination just ran wildly.