It is actually, Walk right and them a jumpscare comes. It gets boring quick. As ThisIsPaulTheMailman said, It is not sonic layout. The screams sound like it was took b a YouTube video and they copy pasted the audio. The image is not terrifying at all. Whoever made this game failed at what they're aiming for. I don't know why they call this a "Creepypasta" anyways.
There are a whole lot of things that makes sonic.Exe not scary. It WAS posted in a trollpasta site. When I played it for the first time, I was shocked/scared, but I guess that because I saw the Sonic.Exe image, I did get scared. But later, it didn't scare me, because the element of surprise ended. The important thing is to keep the player surprised, rather than just like, what? 2 minutes?
It isn't scary because it's one of those 'scary cursed games omg!111!!' But it is kind of trippy and suspenseful. The plot is just a really decent mediocre story that doesn't really seem to fit into the creepypasta theme. But it isn't that scary in its entirety. Just the pictures shown on the game can be viewed as a bit spooky and creepy but not scary.
It has a lot of suspense but otherwise it is very boring. It is basically about a drugged up talking hedgehog who is a mass murderer. The "levels" are not sonic layout AT ALL. If you don't believe me look up "teens react to sonic.Exe" and click on the video.