Sure, here is an example of a single HTML file that implements Conway's Game of Life as a playable game using JavaScript:
Save the above code into a `.html` file and open it using any web browser, you can then click on the cells to toggle their state and use the "Start" button to start the game. The game will apply the rules of Conway's Game of Life and animate the grid accordingly. You can use the "Pause/Resume" button to control the game's state and the "Reset" button to reset the game.