Notes

The volume for this game is TOO LOW!
When the game is running, hit F2 to get to the internal service menu. Hit F2 again to "close" the service switch so that you won't get stuck in the menu. Now, navigate to the "Volume Adjust" option (following the directions provided) and adjust the volume. It's best to keep the volume no more than 80-90% filled as it might cause your sound to be overdriven and crackle. When adjusted, simply exit the menu.

How do I calibrate the guns? Can I use a real light gun?
The game will automatically ask you to calibrate the guns when you start the game for the first time. Simply put, use your mouse or keyboard to "target" the top left corner when the game asks so. There aren't any visual cues to help this, so you'll have to go by the numerical coordinates that are visible on the screen. The numbers you see are in a simple 8-bit scale going from 0 to 255. To "target" the top left corner, keep moving your mouse until you get P1 X and P1 Y as near to 0 as possible. The middle is located at about 127, 127, and the bottom right corner as close to 255 as possible. Repeat the process for the second player. As for the light gun, the short answer is no. A longer answer is that the game didn't actually have a light gun — it had analog joysticks mounted as guns, and emulating them with a proper light gun is not viable. Try to use mouse control with this game.