SCP-087 is a first-person horror game that is mainly involved around the player walking down flights of stairs for a long time. While going down these stairs, some scary events happen on certain stairways, and is sure to scare those playing it. It is a very dark game and may be a little too slow for many players. The game is free, however, so if you want to give it a try you can download it via the link below. It is worth the play through if you have the time.
There are now multiple other games in the SCP lineup that you can download through the same link. To list all of the different games that bear the name SCP would take quite some time. They all follow a similar premise as the original, although some have changed up the formula quite a bit. Feel free to check them all out.