Sure! Here's a basic implementation of a simplified version of Super Mario Bros as a single HTML file using JavaScript:
To play the game, save the code as a `.html` file, open it in a web browser (preferably on a smartphone for mobile operation), and you'll see a canvas with a Mario character. You can control Mario using the arrow keys (Tap on them on a smartphone) to make him move right, left, and jump. This is a basic implementation and can be expanded upon to create a complete Super Mario Bros game.