Sure! Here's an example of a snake game implemented as a single HTML file, with JavaScript code enclosed in script tags:
To play the game, you can open the HTML file on a smartphone or in a web browser. The game board will be displayed as a 400x400 pixels canvas, and the snake (represented as green squares) will move around the board to eat red food squares. The game will end if the snake hits the edge of the board or collides with itself.