How will open all levels of igi1?

To unlock all levels of IGI 1 (I'm Going In), you typically need to use a cheat code or modify game files, as the game does not provide an official method for level unlocking. One common cheat code is "GODMODE," which grants access to all levels. Alternatively, you can use a trainer program designed for the game to gain access to all missions. Always ensure to back up your game files before making any modifications.