If a site claims to have an official PS2 version, do not trust it. Why Assassin's Creed Skipped the PS2
"Men must be free to do what they believe. It is not our right to punish them for thinking what they do... Educate them. Teach them right from wrong. It must be knowledge that frees them, not force".
The PS2 version suffers from severe frame drops in the original hardware (dipping to 15-20 FPS in the crowded city of Acre). With PCSX2, you can fix this: