Sure, here's a simple Zombie game implemented as a single HTML file using JavaScript:
To play the game, you can copy and paste the above code into a new HTML file and open it in a web browser. The game canvas will appear, and you can control the player using the arrow keys on your keyboard. The goal is to avoid the zombies and survive as long as possible. If a zombie touches the player, a game over message will appear, and you can reload the page to restart the game.