Sure! Here's an example of a simple game where you can jump and adventure with unlimited items and lands using JavaScript in a single HTML file:
In this game, a red square represents the player. By pressing the up arrow key on a smartphone (or any keyboard), the player jumps vertically. The game loop constantly runs to update the game logic or move the player. You can extend this basic structure to add more features, such as generating unlimited items and lands, and including pictograms or images for a better visual experience.
Remember to further develop the game according to your requirements and design preferences.