Playing the "Sonic.exe" game simply involves moving using the arrow keys and running away when Sonic arrives. This is a 2-D side scrolling horror game made by independent developers.
"Sonic.exe" is a heavily modified version of the original Sonic the Hedgehog game. It was popularized by a creepy online story. The game is a horror game where evil Sonic hunts down and murders all of his allies from the original Sonic the Hedgehog series, such as Knuckles and Tails.
Players start by game by controlling Tails and use the right arrow key to move and space bar to jump. Eventually, Sonic pops up on screen in an attempt to scare players. Players must attempt to run away from Sonic in a hide-and-seek sequence using the left and right arrow keys to move left and right and space bar to jump. Sonic intermittently flashes on screen for a few seconds in an attempt to scare the player. Simply try to avoid him for as long as possible.
Eventually, Sonic catches Tails, and the game progresses to the next stage. In this stage, players play as Knuckles as he runs through various hills to ultimately get found and chased down by evil Sonic. Use similar escape tactics to escape. The game ends when all characters are killed.