Suggestions:
add a Dream x10 girls to make the experience less tedious. The animation for dreaming each girl is too slow and not having the option of making things faster makes it annoying
Given that the point of each level of Relationship is to see the girls with less and less clothes, why not just do fully clothed at the start, then underwear, topless and finally nude for each of the respective levels of Relationship instead of just some hearts?
Reduce the cost of upgrades. Everything is too expensive at the start without reason except for artificially extend playtime. you are gonna grab more people's atrention if you start with a low upgrade cost and exponentially increase it over time