Sure! Here's a simple stickman army war game implemented as a single HTML file using JavaScript. It will work on smartphones and uses pictograms for stickmen representation:
In this game, stickmen are represented as simple rectangles on a canvas. They move randomly within the canvas boundaries. The game continuously updates the stickmen positions and redraws them on each frame. You can further enhance the game by adding user interactions, more game elements, scoring, etc.