Sure! Here's the implementation of the game you described using HTML and JavaScript. The game will display the player as a blue square and the zombies as red squares. You can control the player using a virtual joystick and shoot the zombies by pressing the "L" button on the right.
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To play the game, save the code in a file with a .html extension and open it in a web browser. The game will run and you can control the player, shoot the zombies, and win the game by eliminating all of them.