Well it's an old game, but great potential.
Lot of thinsg looks squarry caus it's BSP based and lot of textures brigthness or colors don't mix.


In fact you could redo your game to today standards by
choosing a non realistic look : lot less work than doing big realistic textures.

Some photoshop filter to bring a cartoon look like in the last
PRince of Persia game for example.



Or plain colors with a pencil drawing shader like on the game Valkyrie Chronicles on PS3 :