Sure, here's an example of a simple game called "Pixel Smash" implemented as a single HTML file:
To play the game, simply open the HTML file in a web browser (preferably on a smartphone to get a better experience). The game involves moving the paddle using mouse movement to bounce the ball and smash the pixels (represented by bricks). The objective is to clear all the pixels by hitting them with the ball using the paddle. The score is displayed at the top left corner of the canvas. If the ball falls below the paddle, the game is over. If all the pixels are cleared, a "Congratulations" message is shown.