The PlayStation 2 used DVD-ROMs, storing between and 8.5GB (dual layer) of data. Standard compression (like ZIP or RAR) can shrink a game by 10–20% by removing empty padding data.
To give you the best advice on high-compressed PS2 games, could you clarify: high compressed ps2 games
Are you looking to on a PC, or for a physical PS2 console using OPL? The PlayStation 2 used DVD-ROMs, storing between and 8