Sure, here's an example of a dark scary maze game implemented as a single HTML file using JavaScript:
Please note that this code provides a basic structure to start implementing the game. You would need to add additional logic to handle the maze, scary elements, game over conditions, win conditions, etc. The provided code sets up a canvas to render the game, draws a player character, and allows for handling keyboard input for movement. Feel free to modify and enhance it to create your dark scary maze game.