Sure, I can help you create a simple game using JavaScript in a single HTML file. Here's an example of a dinosaur-themed game, where you control a character to avoid obstacles:
In this game, you control a dinosaur character using the spacebar (jump) to avoid cactus obstacles. Your score increases as you successfully avoid obstacles. If you collide with an obstacle, the game is over. The game is played on a canvas element with a width of 400 pixels and a height of 200 pixels. The pictograms for the dinosaur and cactus are assumed to be available as `emozi_all/game.png` and `emozi_all/cactus.png` respectively.