Well crafted all around. The place is labyrinthine, but distinct enough that can know where you are with enough familiarity.
In hunted mode, it seemed like the reaper was a lot less aggressive early on, so the ratcheting difficulty (assuming it wasn't random chance) adds to the tension well.
The controls are a little sluggish, but I can only assume that's precisely so you can't just run past the reaper easily. It's done well enough that it feels fitting for the game, and adds to the tension.
The cats are a good way to spook people in Hunted mode, too. That flash of movement of a cat running around as you round a corner is a nice touch.
Hunter mode's online leaderboard felt a bit un-GameBoy-y, but it's basically a speed challenge as it is anyway, so I know why it was done.