Sure, here's a game implemented in a single HTML file, using JavaScript enclosed in script tags:
Pictogram Game
This is a basic implementation of a game where the player rushes at anyone they see and pushes them. The player can move in four directions using the arrow keys. If the player hits a wall, they stop. The game is represented by a blue square moving on the canvas. You can extend the game by adding functionality for breaking windows or adding more objects to interact with.