What game version did you try to launch (public or paid version)? Also, what platform did you use (Win/Linux/Mac) ? There should be a GuiltyForce_Data folder in the same folder as the application file, I guess.
I will change the archive format for the new public version into .zip because the .7z format creates so much confusion for the users, lol. I'm glad that it worked after proper extraction, though.
