It looks sharper because the Wii version isn't displaying in 16 bit colour any more. The colours are now look more accurate, rich and the contrast/brightness are more accurate. Dr Salvador's sack texture looks to have been improved.
They appear to be half way in improving the textures.
Capture equipment has also improved. It looks like a frame buffer dump than an output capture.
The PS2 version had lower rezed/colour textures. Lower, less accurate lighting. Lower count models. From the screen shots, they are also rendered too bright.