Nice work! The game is not scary but it is horror themed :)
However, you don't tell the player anything really. Luckily I'm used to playing games, so jumping with space and moving with WASD is something I always do, but if someone else who doesn't play alot of games tries to play this, they might be confused.
Also, there is no indication of what is dangerous and what isn't. At first I didnt think the roses were dangerous because they didn't consistently kill me, but then they started killing me sometimes...
And the darkness around the whole screen just makes the player jump forward and hope for the best, and then you jump into a rose or a gravestone and just die, without the game teaching you that they're dangerous.
I actually think this game would be much better without all the darkness, it would probably be a great rage game if you could see the entire screen. But right now, it just feels extremely unfair playing it.