I do not recommend downloading a random "IGI game zip file" from a forum or file-hosting site.
Project IGI is copyright of Innerloop Studios and Eidos Interactive (now part of Square Enix / Enad Global 7). This article is for educational and archival purposes only. Downloading the game for free occupies a gray legal area. If you want to support the developers, consider playing the spiritual successor, "I.G.I. Origins," which is currently in development. We do not host any copyrighted files directly. igi game zip file free download