The player's collider is very big, it can get hit by anything, and most of the time it looks like the player got killed by nothing.

Also, hiding an obstacle under tha ground is not a good way to make the game harder. Not all people will see the tiny white pixels, and not all of them will realize what is killing them.

Even though, the game is still entertaining enough. I dedicated my time into trying to beat it. I hope you read my comment and it helps you for future games :)