So yeah, I got it, and along with Arcanum, it's not working. After starting the game, the menu works fine, but starting in the opening cinematic, I get a large amount of lag that I don't understand.

I have a nVidia GeForce 9800M GT.

Any idea what's wrong?

Same problem here. I get music playing and can see some blurry figures sitting near a fireplace and the bottom part of the screen is black. I have to ctrl alt del out of it.

why don't you guys check older threads?
here's one
http://www.gog.com/en/forum/the_longest_journey/choppy_performance/ , posts 14, 18, 19. should work.

That's what I did:

1. edit "C:\Users\AppData\Roaming\The Longest Journey\Preferences.ini":
'[DirectX]
bool_UseHardware=0'

2. configure.exe in your game directory:
'Force single buffer': enabled
'Force 16bit mode': enabled

That did the trick for me. I'm running the game in fullscreen on a notebook with a GeForce 9600M GT and Windows 7 (64 Bit).