Here's a simple shooting game implemented in a single HTML file using JavaScript:
To play the game, just click on the red targets as they appear on the canvas. You earn 10 points for each target hit, and the game ends when you reach a score of 100. You can also adjust the canvas size (320x480) and the target speed (controlled by the `vx` and `vy` variables in the `Target` constructor) to make the game easier or harder.