It's a really interesting idea. The difficulty curve could use a little work though; I struggled to make it past day 0 on most of my attempts, so I didn't get to see anything past the city design.
The entity is suitably creepy though, and I did get a sense of dread the first time it came charging at me, I just wish I had more options for getting away from it. Maybe limit how fast it turns so it's possible to feint and gain some distance?