I wasn't sure what to expect upon starting up ERIE. Possibly because of that, it ended up being a very neat half hour gaming experience. The game is pretty simple overall. You begin in a pool of water with no idea of where you are. Quickly, you read papers scattered around which start to inform your understanding of the location and what happened.
Unfortunately I'm still not completely sure as to the specifics, but it seems like a game best played when you are unaware of the story anyway. Without knowing anything you can enter the game with a fresh perspective! I would recommend that as it helps make everything a bit scarier and interesting as events unfold.
In regards to gameplay, it is quite simple. There's little you ever have to do aside from marking your pathways as well as collecting a few key cards. Well, you don't have to read letters or mark your way, but it just seems something most players are going to do. Although you are not given explicit goals, it quickly becomes easy to understand what to do. Level design is also not bad. Even for someone like me who tends to get lost without looking at a map every second I was able to get a feel for my surroundings (eventually).
The game is very eerie and contains a few "boo" moments. For a little while, I felt legitimately annoyed, until discovering things were not as hard as I was making them up to be. Overall, this is a great little gameplay experiment if you want to play something spooky.
PS: The video up top is my first playthrough of the game, which took around 30 minutes.