Sure! Here's a simple implementation of a 2D side-scrolling platformer game using HTML, CSS, and JavaScript:
This HTML file includes the implementation for a simple side-scrolling platformer game. It uses a red ball as the player character and blue rectangles as the platforms. You can control the player by pressing the left and right arrow keys to move and the spacebar to jump.
Note: You can copy and paste this code into an HTML file (e.g., game.html) and open it in your browser to play the game.