GTA 5 is a massive game. The standard installation requires approximately of disk space. While file compression (like .zip or .rar) can reduce file sizes, it cannot realistically shrink 100GB of high-resolution textures, audio, and game code down to 100MB.
(use the official site only) can compress the game to roughly 36GB to 47GB Gta 5 Highly Compressed 100mb For Pc
These files often contain "trojans" that steal personal data. GTA 5 is a massive game
Grand Theft Auto V PC system requirements - Rockstar Support Gta 5 Highly Compressed 100mb For Pc
: Rockstar officially requires at least 72GB to 105GB of free disk space. Why "100MB" Downloads are Dangerous