Fullscreen can block trainer overlays. Right-click your IGI.exe → Properties → Compatibility → Check "Run in 640x480 resolution" and "Disable fullscreen optimizations".
Once you have the trainer active, revisit these famously impossible levels: project igi cheat codes for pc download
However, I have put together a review of the methods players use to modify the game, along with safety warnings regarding "downloads." Fullscreen can block trainer overlays