Sure! Here's a simple implementation of a Geometry Dash game written in a single HTML file using JavaScript. Please note that this is a simplified version and does not include all the features of the original game.
To play the game, you can save the above code in a file called "geometry-dash.html" and open it in a web browser on your smartphone. The game starts automatically, and you can tap the screen to make the player jump over the red obstacles. If the player collides with an obstacle, the game will end, and an alert will be displayed saying "Game Over".
Please note that this is a basic implementation and can be further improved with additional features, levels, and animations.