The SUSPENSE. It was SO unnerving, the atmosphere was NAILED, on the SPOT.
...Then the monster showed up.
My recommendation is to keep the monster's appearance a mystery until the VERY last second, because the reveal kind of took away from the overall nightmarish sense of dread.
Like, maybe have it shuffle around in the room where your camera can't look while you're forced to progress the game on the TV? See nothing but lanky limbs slipping just out of your view behind you?
Other than the reveal of the monster midway through and the jumpscare being a little funny, this was amazing. The concept, the graphics, the audio, and the looming fear of whatever it is that you're inadvertently leading right to your room through a video game made for the first horror game to make me feel realistic dread in a long time.