You do a great job of making the backgrounds feel like real spaces. I think your use of perspective and lighting help that believability (I really like, for example, the top-down CCTV shot you have for the main menu and how a part of the hallway illuminates when the lights turn on in the next room). Also appreciated the twinkling star art he has up on the walls, the flowers/plants in his bedroom, and of course that adorable plushie.
I imagine it takes a long time to come up with and polish all these assets, so I'm glad you're taking the project at your own pace! It's such a charming project so I wish you the best with its development :)