Sure! Here's a basic example of a game similar to Mario, implemented as a single HTML file using JavaScript:
This example creates a simple game window with a red square representing the player character. The player can move the character left or right using the arrow keys. The game loop runs every 16ms to handle game logic, but you would need to implement the actual game mechanics and behaviors within the loop for a fully functional game.
Please note that this is just a basic template to get started, and you would need to further develop the game by adding collision detection, enemy characters, scoring system, levels, and more.