I got home really late last night so I didn't get to play much, but very impressed with the improvements so far. Looks much richer than the original. The textures are more pronounced and the animations even more lifelike. Better lighting effects, more fish - a lot more, schools of fish are now a school of independant fish that follow each other, plant life looks better, etc., etc. I could go on and on. Very impressive.
Humans are still stiff but not as bad as in EO (which was laughably bad in that regard). My only complaint so far is I don't like the rigidity of the storyline but I guess that's just the beginning until you've learned everything you'll need to know and also that there's a lot less info about the fishes. I prefer getting more and more details about them on addition trips.
Not sure how I feel about the pulsar but I'll admit it was a little ridiculous being able to go pet sharks and such without fear of attack so I appreciate the added realism but not sure if I'll enjoy shooting them or if it'll just be annoying.