We've still to do the final pass on the missions when they'll be balanced properly, but the missions should respond to the difficulty setting you adjust the game to. The difficulty we've balanced it is for it to be played on Medium, and it really should be that, not too easy but not too challenging either.
I have doubts whether or not it can be completed on Insane though, but I haven't tried it personally.
As far as the installation itself goes, we're looking at making BWO (depending on Ace largely I'd say) a standalone installation, much like Battlestar Galactica works. You download one file, it installs to a separate directory and it's more or less its own game.
Short of that, it'll play just like any other mod, selecting it from the lancher, etc.
