JeSpre,
The demo crashed on me quite a bit. I did find a demo patch and installed it. No idea yet if it makes the demo more stable. I'm running the 6.18 drivers right now....need to update those, too, I suppose.
Jumping puzzles?

Damn, I hate those! They were most lame in Heretic 2 (there was one hub near the end that had a whole level devoted to ducking and jumping and I truly hated it).
I read a review that said the game is very short. Hmmm....I may wait for it to appear in the bargain bins.
Heretik,
the protaganist is a cutie, to be sure, but that's not why I'd buy the game.
I will say one thing: they did an incredible job in creating a beautiful gaming environment. Best use of the Q3 engine yet though I know some feel ST: Elite Forces is equally good.