Pretty damn scary. The fnaf style of having to check multiple things while a clock ticking down was handled quite well plus it does a good job at feeling distinct. The art and sound design is good and the instructions were clear. However I think the closet is unfair to deal with because no matter how long I kept closing it, it just continued to open which eventually always killed me. Also the jumpscare noise is extremely loud which I didn't love. Adding settings to adjust volume as well as adjust sensitivity would be good.
But what you have is pretty nice. Other than all that, maybe if you add some more sound effects and make it obvious how long you need to survive for, then it would become quite enjoyable. Good game regardless!