Sure, here's an example of a simple billiards game implemented as a single HTML file using JavaScript and enclosed in script tags:
Billiards Game
In this implementation, we have a green game board with two balls, the cue ball and the target ball. By clicking on the cue ball, a shot is simulated where the cue ball moves towards the target ball based on the angle between them. The strength of the shot can be adjusted by modifying the `moveDistance` variable.
Please note that this is a basic example and there are many possible improvements and features that could be added to make a more complete billiards game.