I do like the fact that as best I can tell you can do most anything you want in the game, and winning or losing at end is mostly the only penalty, (as in losing to the main boss or winning).
And adult game that lets you do adult thing's with out instantly getting a bad ending because you did some fucking around, (that is sort of novel).
(I might be wrong, I have beaten it only the one time, and am at present doing some of the extended stuff, but I was promiscuous as all get out on my first play-through, and I seem to have gotten a good ending.)