Sure, here is a sample implementation of a platformer game using JavaScript, HTML, and CSS:
This code sets up a simple platformer game with a character represented by a blue box and an obstacle represented by a red box. The player can control the character using a virtual joystick by clicking and releasing on the character. When the joystick is released, the character launches upwards, and the player needs to avoid colliding with the obstacle. If a collision occurs, a game over message is displayed, and the game restarts.
Please note that this implementation is functional but quite basic. You can enhance it further by adding more features, levels, and graphics as per your requirement.