My experience with tomb raiders since it has landed on the PS2 was horrible. Thank god Eidos decided to change the studio to save the franchise. Last year I enjoyed very much tomb raider anniversary, a game I gladly finished and since then I wanted for more. 
Tomb Raider Underworld is much prettier and seems to be designed for this generation without the hooks of previous platforms and it shows. The engine is beautiful and well optimized on PC, it shows vast and colorful areas with good textures, effects and great enemies models, and should I mention this is the greatest Lara model so far. I also loved the zen fairy music in the level, it matches the mood perfectly along with great sound effects .
The game starts on your yacht and we all have seen that demo on videos. Lara controls just right, from cliff to cliff with good animations until I reached the road that leads to the temple. I haven’t been bothered with a wacky movement and I like that fast grip implemented since tomb raider legend. However, the camera wasn’t bright as you should in some few occasions guess where to jump. This problem gets bad when those first three tigers appear and they try to surround you, the camera do not zoom out making it impossible to see from where their claws are coming. Making things worse, lara isn’t really a fast jumper so the best way to deal with them is to eliminate them from far away, once they are very close things get ugly. Lara movements are well animated except that atrocious rag doll death animation which should be eliminated asap. I have no idea how developers could leave it there, they certainly could do better in that area… Well, perhaps it does not matter when you are dead anyway. 
Later in the level, you will need to solve a simple puzzle based on observations; few jumps from right to left and you’ll get done with the demo.
I liked what I played and I’m definitely eager to play the game, you truly feel like Indiana Jones in those ruins. Graphics, sound , control it’s all great. Too bad camera problem rears its ugly head on some instances and I wish Lara could jump a bit faster. Oh And let me take a shit on that ragdoll animation when you’re dead.

The game was tested on a ati 4870, q6600 3ghz, 4gb.
All details max, 8AA, 16AF , 1440*900 (very few micro stuttering observed) 
Using xbox360 controller  
Average FPS 75