Better draw distances, improved textures, and more vibrant lighting effects.
While the PSP version was groundbreaking for handhelds, the PS2 port brought several enhancements that make it the definitive way to experience the story of Vic Vance:
Use ZArchiver (Android) or 7-Zip (PC). Enter the password if the file is protected.
Grand Theft Auto: Vice City Stories – Finding the Best PS2 ISO Highly Compressed