Shademp
420
The short answer is that PS2 emulation is complicated and Dirge of Cerberus would require a unique game fix hack or other plugin to make it work well on most computers. So far, nobody with the skill and interest is yet to write up such a plugin for the game.
You will notice in places that even on console the game will sometimes suffer from frame drops. Places like the Shera (Chapter 7) and any area with lots of particle effects and explosions will make the game lose frames. This makes precision gameplay more difficult, so aiming in certain segments becomes way harder because of the frame drops. So my assessment is that Dirge of Cerberus is uniquely optimized for the PS2 but will show performance cracks even on original hardware if you know where to look.
You will notice in places that even on console the game will sometimes suffer from frame drops. Places like the Shera (Chapter 7) and any area with lots of particle effects and explosions will make the game lose frames. This makes precision gameplay more difficult, so aiming in certain segments becomes way harder because of the frame drops. So my assessment is that Dirge of Cerberus is uniquely optimized for the PS2 but will show performance cracks even on original hardware if you know where to look.