You will likely need to run the .exe in Compatibility Mode (Windows XP SP3) and as an Administrator .
The full game is roughly 1.2 GB to 1.5 GB . If your .rar is significantly smaller (e.g., under 500 MB), it may be a "repack" with compressed/missing cinematics. Impossible.Creatures.rar
Reviewing a specific download from the web requires caution. Based on common community feedback for this specific archive on sites like the Internet Archive : You will likely need to run the
Over 50,000 possible creature combinations (e.g., a Cheetah with Great White Shark jaws). under 500 MB)
Relic Entertainment (creators of Homeworld and Dawn of War ).
High creativity, fun campaign, and distinct visual style.