Here's an example of a game implementation using JavaScript and HTML. The game is a simple platformer where the player controls a black triangle.
In this game, you control the black triangle using the arrow keys on a smartphone. Tapping the left arrow key moves the triangle to the left, tapping the right arrow key moves it to the right, and tapping the up arrow key makes the triangle jump/fall 90 degrees. The spacebar key is not used in this game.
Note: This is a basic example and may not include all the functionality or visual design desired in a fully-fledged game.