I keep hearing that this game is too easy if you play on normal, but I just HATE when I'm halfway through a game and I feel the need to lower the difficulty.  I'm ultimately going to be playing the XBLA version, but I'd even like to know if you can lower the difficulty in the PC version.  I doubt that they would remove that feature of the game, and I doubt many of you reading this have played the XBLA version.   
 
So, is this something that I should be worried about or not?

No, you can't. And Normal is easy from the beginning.

" No, you can't. And Normal is easy from the beginning. "