Sure! Here's a simple game implemented as a single HTML file, where you can control a character using smartphone navigation buttons (represented by pictograms) and collect coins. The goal is to collect as many coins as possible within a time limit. Please note that this is just a basic example to demonstrate the concept.
This game creates a game board with a player character (represented by a red square) and randomly placed coins (represented by yellow circles). You can navigate the player character using the "left", "right", "up", and "down" pictogram buttons. As you collect the coins by colliding with them, your score increases, and the remaining time gets updated. Once the time limit (30 seconds) is over, the game ends, and you are alerted with your final score. You can restart the game by clicking "OK" in the alert.
Please note that this is a basic implementation and can be expanded upon with additional features, improved graphics, etc., based on your requirements and creativity.