Henry
Autoexreginated
Sam, WayneLigon, and the good Colonel pretty much summed it up, but the only other thing to add is that you will see a lot of discussion here and there about "which system is better" to play the game with - the original game system by Chaosium (BRP), or the one that WotC designed (d20).
To me, the original system fits the concept of plain humans fighting to stave off cosmic horror and insanity. The d20 version is slightly more heroic in that, since characters gain levels and therefore hit points, they can take a LOT more "nickel-and-dime" punishment overall, although the way the system is built, one REALLY solid hit or gunshot will be fatal. And big 20 foot tall monsters with tentacles are ALWAYS fatal.
If you were rating them as movies, the original system would have a feel more like Steven King's "The Stand," while the d20 version would feel more like Friday the 13th, or the Halloween series.
To me, the original system fits the concept of plain humans fighting to stave off cosmic horror and insanity. The d20 version is slightly more heroic in that, since characters gain levels and therefore hit points, they can take a LOT more "nickel-and-dime" punishment overall, although the way the system is built, one REALLY solid hit or gunshot will be fatal. And big 20 foot tall monsters with tentacles are ALWAYS fatal.

If you were rating them as movies, the original system would have a feel more like Steven King's "The Stand," while the d20 version would feel more like Friday the 13th, or the Halloween series.