Sure! Here's a simple example of a text-based game that combines elements of Pokémon and Avengers. Since it needs to be a single HTML file, I'll incorporate the JavaScript code within the `` tags.
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When you open this HTML file in a browser, you'll see the game's output in the browser's console.
Please note that this is a very basic implementation and only simulates battles between Avengers. In a complete game, you would need additional logic, user interaction, graphical elements, and more robust gameplay mechanics.