Sure! Here's an example of an incremental game implemented as a single HTML file, using JavaScript enclosed in `` tags:
<br><br>
<br>
<h1>Incremental Game</h1>
<p>Click the button to increase your score:</p>
<button id="incrementBtn">Click Me</button>
<p id="score">Score: 0</p>
In this game, the player starts with a score of 0 and can click the "Click Me" button to increase their score. The score is displayed in the "Score: X" format.
Additionally, there is a functionality to buy a score multiplier upgrade by spending 10 points. However, this feature is not fully implemented here, and the player's score does not decrease when purchasing the upgrade. It's a simple example to demonstrate the concept.
You can further expand this game by adding more features, buying upgrades, unlocking new abilities, and so on. The possibilities are vast, but this example should give you a starting point for creating an incremental game using JavaScript and HTML.