Ps2 version does not boast the amazing graphics that GC version did, but it still looks great and has no frame drops.
Here's an overview:
Gameplay:
+no diff from GC version (maybe less enemies in some areas but you barely notice it)
-no puzzles (well there are but, if it takes 2 seconds to solve them then thats just a filler)
Graphics:
+30 frames of constant laggless gameplay
+true widescreen and 480p
+the level design remains unchanged
-downgrades are pretty big
-enemies look worse
-all realtime lighting is gone (including the stunning lightning strikes seen on GC, muzzle flashes)
Sound:
-WTF!? the quality is actually quite a bit worse than GC
-crap ass music pfff
+still cool sounds overall
Value:
+more **** than in the GC version! (just rent if you have the GC version)
Anyway, this is awesome so go get it.