Every time I go to feed on someone the game hangs, it is like it's just lagging really really badly. If I click escape (fast enough) and go back to the main menu and load a different game, it starts off doing the same thing.

Also, for some reason when I feed off the first guy in the tutorial it doesn't happen. The game runs fine otherwise.

Help?

Had the same problem and scoured the Interwebs looking for a clue. Here's what worked for me (and I was crashing about every other feed and couldn't ever feed during combat):

Add:
-dxlevel 70

to the VtM shortcut. This forces DirectX to use the older version 7 drivers. Suddenly, I can feed! Even during combat!

For the record, I'm using an ATI card with the latest graphics drivers.