Sure, I can create a simple game using JavaScript and HTML. Since you mentioned Mario, let's create a game where Mario must collect coins while avoiding obstacles. Here's an example of how the game could be implemented as a single HTML file:
To play the game, you would need to have Mario, obstacle, and coin images in the same directory as the HTML file, and update the `url()` paths in the CSS accordingly. Note that this is a simplified example, and you can make the game more complex by adding additional features, levels, and animations, as per your requirements.