Sure, here's an example of a text-based choice game set in medieval times, implemented as a single HTML file using JavaScript:
In this game, the player starts by entering their name and is then prompted with different scenarios and choices. The game keeps track of the player's health and displays it throughout the journey. The example provided includes three scenarios, but you can expand the game by adding more scenarios, choices, and game ending logic as needed.
Please note that this is a basic example and can be further improved and customized based on your specific game requirements and design preferences.