Sure, here's a simplified version of the Bloons TD 6 game implemented as a single HTML file using JavaScript. Please note that it's a basic implementation and doesn't include all the features of the original game. The game will be playable on a smartphone.
This is a basic implementation where balloons move from left to right, and you need to click/tap on the screen to shoot projectiles to destroy the balloons and earn points. The game will end after you run out of lives. The score and remaining lives are displayed on the canvas. Please note that this is a simplified version and doesn't include all the features and complexity of the original Bloons TD 6 game.