Wow, I enjoyed this game. I've been planning on experimenting with Ink, and your game has solidified that plan. I love how the story moves through these simple descriptions of the flat and the surroundings; I was really able to dive into the setting. I also loved how the colors complimented the story, particularly as the paranoia sets in (regarding the shadow). I have just a few minor comments/recommendations:
1. I liked how many of the choices seemed to be filling in sentences. But I think that would be extended by having them actually do that in the text, instead of having a paragraph break where they continue. Think the first choice I made had this.
2. There are a few places where you can cut repetitive words that won't alter the story. One that drew my attention was, "My finances are a mess and this place is the only place anywhere near my..." I would cut the first "place" as it is unnecessary. I also saw a few missing periods ("They must have seen me They must be here to do something to me"), but again these are incredibly minor.
3. While I did like the color changing, I got to a point where it changed to purple, but all the text was the same from before. Is there a way to make it more seamless? I ended up just rereading all of that text as I was unsure if I was missing something.
But as I mentioned, these are all very minor in contrast to the excellent story you have created. I thank you for letting me play/read it and thank you for sharing it!