Sure! Here's a simple text-based zombie fighting game implemented as a single HTML file using JavaScript. You can access it in a browser, including on a smartphone.
To play the game, open the HTML file in a web browser. The game will start automatically, and you'll see the battle progress and the remaining health points for the player and the zombie in the browser's console. The player and the zombie attack each other alternately until one of them is defeated. Good luck fighting the zombies!