Sure, I can help you create a simple game with a boss fight using JavaScript. Here's an example implementation:
In this game, you control a blue player character using the Arrow Up and Arrow Down keys on your smartphone. Pressing the spacebar shoots black lasers towards the blackie boss character. If a laser collides with the blackie boss, you win the game.
Note that due to the limitations of text-based communication, this example may not be perfectly tailored for smartphone use and pictograms. However, you can modify the code and CSS styles to better fit your requirements.