Sure! Here's a basic implementation of a 3D FPS game that includes a tutorial, using JavaScript and enclosed within script tags in a single HTML file. Please note that this is a simplified version and may not have all the features of a complete game.
In this example, I've included a placeholder `<div>` element (`gameCanvas`) that represents the game canvas where the game will be rendered. The tutorial section displays instructions or images to guide the player on how to play the game. After the tutorial, the game loop starts and continues until the game ends.
Please note that this is a basic structure, and you'll need to add additional logic, game mechanics, controls, assets, and rendering techniques to create a complete 3D FPS game.