To sum it up: Completely unplayable.
The graphics are actually so good that they're bad. Bad in that the frame rate is just laughable. I just got done playing Turok 1 on the 64 and was very much looking forward to the sequel... what a disappointment.
I first tried playing with the expansion pack with the high res mode turned on. It looked great, however I couldn't aim or jump accurately to save my life. At one point I was shooting the pistol down at a dino from above as he ran around in circles. I couldn't move the joystick to aim for him (as it was near impossible to control), I just waited for him to come back into my sights. This process took me quite a while as the dinosaurs take a few bullets to kill.
After playing with the high res mode turned on and realizing I wouldn't be able to play it like that, I turned the resolution to low. I hardly noticed any improvement at all.
I then went on IGN to hear what professional reviewers were saying, IGN gave the game a 9/10 and even noted the lag issues! I couldn't believe it. They mostly praised the multiplayer mode... but when I played the game years ago as a kid, I wasn't too much of a fan especially considering Goldeneye existed.
As a last ditch effort I tried to play with just the jumper pack as opposed to the expansion pack. However, this didn't help at all. I decided to put some cheats in and see if the other levels were laggy and yes it was so. I even did a boss fight and that is where the lag was the absolute worst. Must have been about 3 frames a second... kind of like a fast slide show.
All in all I am just incredibly disappointed. I am aware there is a PC version, however I don't think I will attempt to obtain that as I just wanted to play on my 64.
What's hilarious is the reviews on gamefaqs. Take this excerpt for example: "Usually, most games that have outstanding graphics are sort of choppy and the graphics aren't steady and smooth, since they spent so much time on the graphics themselves than the smoothness. Turok 2, however, is a refreshing exception. What makes Turok 2's graphics so great is that they are all very detailed, but very smooth also. The only times the game may slow down a tiny bit is when there is a massive amount of gunfire and activity on the screen at once (but then again, what game doesn't get choppy at some point?). Aside from when their is a bombarding amount of gunfire, the rest of the game is very smooth. You easily swim without and choppiness and you rarely see any screw-ups with the graphics. I think one of the reasons the game is smooth is because the levels are divided into sections via warps. Without the warps, the levels would probably be much more choppy. It really feels like you are in the game when you move around, too. All-in-all, Turok 2 is very smooth (especially smooth considering the perfect graphics). "
I guess many of us were tricked back then.