Sure! Here's an example of a simple battle royale game implemented as a single HTML file:
In this game, you'll control a blue player using arrow keys on your smartphone. The goal is to survive and become the last remaining player in the battle royale. As you move around, other players (represented by blue boxes) will also move randomly. If you are the last player remaining, you'll win the game, and an alert will notify you.
Note that this is a basic implementation and can be expanded upon to include more advanced functionalities, battle mechanics, and graphics if desired.