From the moment the game started, I was amazed by the UI and the aesthetics. As an Rpg Maker user, I know how hard it's to implement stuff like this, specially using so many pictures, so that's amazing and really admirable.
The plot was simple, but effective, and I really liked the setting. The story isn't thrown at your face, you get it by examining the place and objects, like for example, the IDs in the bed or the e-mails. The game doesn't outright tell you "hey, a frustrated serial killer lives in this apartment". That's something you put together by paying attention, that was really good.
The art was incredible and I loved the palette used. Also, I liked how villain looked more inhuman (I'm still unsure  if he was really a monster, or that was just because the MC was kinda hallucinating) compared to the other characters, as a way to reflect his inhuman nature.
The endings were pretty concise, but highly effective, specially since they were accompanied by short texts about real painters/paintings that gave the endings a stronger feeling.
I also want to praise the gameplay. Map navigation was really cool, I enjoyed observing everything in each room, it kinda reminded me of PC-98 games. The atmosphere was also really good, and I felt tension after the arrival of the antagonist. Overall, this was an amazing game and I really enjoyed. Amazing work BlueROSE and Broody!