They deleted almost all missions, audio files, textures, and store interiors .
Many sites claiming to offer GTA 5 in tiny sizes (like 500MB or 1GB) are often fake and contain viruses or "surveys" that never give you a working game . gta-5-game-on-pc-highly-compressed-gameboy
Instead of using extreme compression that ruins the game, you can follow an official performance guide to tweak settings for low-end hardware . GTA V Graphics Settings and Mods to Boost Your FPS They deleted almost all missions, audio files, textures,
While it’s not literally a Game Boy game, it is nicknamed "GameBoy" or "PlayStation 1" style because the extreme compression makes the graphics look blocky, low-resolution, and retro . How They Did It GTA V Graphics Settings and Mods to Boost
Modders (specifically credited to ) achieved this massive size reduction by removing almost everything except the "skeleton" of the game :