I'm insanely impressed with the quality of this demo and how easily it runs on an older computer like I have! I think the idea of a huniepop-esque game but with rhythm sequences is very clever and this could really take off if you stay consistent! The character designs are very pleasing and I'm interested to see what you do with their development and routes in the future, assuming you don't actually fully seduce them in the first night like in the demo haha.
The only issues I have with the game are:
1. The difficulty of the rhythm section is a bit too intense, or at least too sensitive. The amount of notes is the only thing that seems to decrease when you lower the difficulty, so I think making the range of getting a perfect on a note wider would help a lot for newer players.
2. As much as I love the character concepts, I really think it's important to change their names before the full release. The genderbent serial killer names are cool and all, but naming them after real serial killers romanticizes their actual murders way too much. These people actually killed and did much worse to hundreds of people, so I don't think a game about romancing them would be very appropriate. If a relative of one of the victims of these murderers played this game they would be extremely offended. Don't get me wrong I see what you were going for, but it's a major oversight.
Other than that, I look forward to the full release and I give you my best wishes in completing it!