Because the game is no longer in official production, digital keys are rare and often sold at a significant premium by third-party resellers.
Downloading games through unofficial channels can violate copyright laws. Consider purchasing the game through official channels like Steam, GOG, or the Epic Games Store if it's available. These platforms not only provide a legal copy of the game but also offer patches, updates, and community support.
When you see a download labeled "highly compressed" (e.g., a 7GB game compressed into 500MB or 1GB), it generally means the files have been shrunk using advanced compression algorithms (like 7Zip or RAR) to save bandwidth.