Sure, here is a simple game implemented as a single HTML file with JavaScript enclosed in script tags:
This game involves moving a red dot up and down as a player tries to avoid it by clicking on the game area. The player's score increases with each click, but hitting the red dot will reset the score. The game is played on a smartphone and allows the player to interact using touch input. The game will keep running until the player hits the red dot and the score resets.