Sure, here's an example of a simple text-based game called "MHA World's Strongest Hero" implemented as a single HTML file:
When you open this HTML file in a browser, it will display an introductory message and prompt you to enter your hero name. After that, it will ask for your actions in a loop until you choose to escape. The game will display different outcomes based on your choices. The game ends when you successfully escape or make a wrong choice.
Please note that this is a very basic example and can be expanded and customized further to create a more engaging game.