This was so good! :D I feel like it's one of those stories that would work really well as a full-length horror movie :3
The sprites are gorgeous, and I know you said the backgrounds and stuff are creative commons assets, but I think they're great choices because they all suit the story really well.
And then there's the soundtrack which was fantastic :3 My personal favourite tracks were the one that starts playing in basement 2, and then the one that starts playing during the reveal. But I love the soundtrack as a whole!
Awesome job :3 The game really is Truly Sublime <3