Sure, I can provide you with a basic shooting game implemented as a single HTML file. However, please note that creating a game with "realistic and cool graphics" may require advanced programming techniques and external libraries, which are beyond the scope of this simple text-based implementation. Nevertheless, I will provide you with a game that you can play, and you can enhance it with graphics or additional features if you like. Please find the code below:
To play the game, you can open a web browser and save the above code into a file with a `.html` extension, e.g., `shooting_game.html`. Then, open the file in the web browser, and you should be able to play the shooting game.
Please note that this is a simple game without graphics. If you want to enhance the game's graphics, you can consider using external libraries like Phaser or PixiJS, or even HTML5 canvas features to draw images instead of rectangles. Additionally, you can include sound effects, animated sprites, and more advanced gameplay mechanics to make the game more interesting.