Sure! Here's a simple implementation of an offline 2D battle royale game using JavaScript within a single HTML file:
This implementation sets up a simple battle royale game with two players represented as black squares on a 2D canvas. The `Player` class defines the player's position and size, and the `initGame`, `update`, and `render` functions handle initializing the game, updating the game state, and rendering the game objects respectively. The game loop continuously updates and renders the game to create an interactive experience.
Note: This is a basic starting point for a battle royale game and does not include features like player movement, collisions, or win conditions. You can build upon this foundation to add additional functionality and features as per your requirements.