Recently, a modder with the nickname OptiJuegos published a gameplay recording of a simplified version of Grand Theft Auto V on social media.
The regular GTA V weighs around 120 GB, while the game client he presented is only 2.5 GB:
OptiJuegos explained that he was able to achieve this result by removing about 98% of the game's content — on a "2015 state netbook" this GTA V runs at 20 FPS:
Goodbye missions, voice acting, [content on the map] and all that! It's amazing that the game still works after such a cut — and, frankly, it's quite playable!
The full recording by OptiJuegos can be found at the following link.