:w00t: There's *tons* of bugs in the initial release! You may have a later version. There's little that'll crash it, but there's a load of problems with some quests (especially the more complex ones, like in New Reno)
Regardless, the game is well-playable without it, but it's better with imo!
One more thing: This demo is a fairly bad representation of Fallout - the actual game has a slightly easier to use interface, and has a good bit more roleplaying; the demo just winds down into a big fight. That's not to say I didn't play it a load of times to see every possible outcome! (Usually me taking everyone on with the minigun
)