Here's an example of a simple game implemented as a single HTML file using JavaScript and enclosed in script tags:
In this example, the game engine is implemented as a JavaScript class `GameEngine`, which has an `update` function to update the game state and a `render` function to display the game on the screen. The game starts when the `startGame` function is called, which uses `setInterval` to repeatedly update and render the game.
You can modify the game logic and rendering code inside the `update` and `render` functions according to your game's requirements. This is just a basic template to get you started.