No I haven't beat the game yet. I have 1-4, 5-2, and 5-3 to beat yet. Check out the wiki linked in the OP for info about world tendancies.
I'm at level 61 and should be able to beat the game shortly, possibly even tonight. We'll see how it goes.
Demon's Souls Official Thread | Currently playing: Left 4 Dead 2, LittleBigPlanet 2, Magicka