Sure! Here's an example of a simple game implemented as a single HTML file, using JavaScript and pictograms for smartphone operation:
This game includes a build section with defense buildings and zombies that attack your base. The zombies move towards the base, but they are super slow with a speed of 1. The defense buildings are represented as green rectangles, and the zombies are represented as red circles. The player's base health is displayed on the top-left corner using text. Feel free to modify and enhance the game as needed.