Sure, here is an example of a simplified implementation of the game "Flappy Bird" using HTML, CSS, and JavaScript:
This is a simplified version of Flappy Bird where you control the bird's movement by tapping/clicking on the game area. The goal is to navigate the bird through the gaps between two moving pipes without colliding with them. If the bird collides with a pipe, the game is over and an alert message will be displayed. The game is displayed on a 320px by 480px game container. The bird is represented by a yellow square, and the pipes are green rectangles that move from right to left.