(Warning, spoilers in this comment.)
Very cool mechanic with the calendar. Story was a bit spooky and mysterious, good stuff. Left interesting questions unanswered too; I like it.
Like, the "device" might have been what helped screw with time? What causes days to repeat? A mixture of Clockheart and the device? After the "ending", how much time passed once we left? What does the world outside look like?
Really enjoyed this~.