Ornstein and Smough weren't cheap, but you could tell the first time you fought them that you would be there for a long, long while.
The run up to them really compounds the whole thing though. fuck that one archer inside the cathedral
it's not uncommon to have one of them dash out of your camera and punching into you,then as your character is all busy kneeling over and doing generaly "getting hit" animation,the other comes and finish you off...
...even after you kill one of them,the other morphs and get an attack that insta-kill you for no other reason than being cheap,cheap,cheap... then you beat him after you discover it's actualy possible to stunlock him with certain attack... i wish we had more approriate rage emoticon

how the actual trailer should look like
you know what was the most satysfing part of dark souls? it was cheating like a dirty rotten bastard in new game+ (because for some stupid gamer pride reason i had to make things fair at least on my side for the first playthrough) and killing them in 3 hits,that is the happiest memory i have of the game... even the final boss is a complete and total wussy compared to them... actualy the whole game just take a huge dip in difficulty after you are done with that huge raging shit that is anor londo
EDIT:

SUMS UP DARK SOULS PERFECTLY