This depends on the requirements of the question...
If we are talking about campaigns (i.e. what is typically considered a "playthrough"), then I'd have to say Killzone 2 on Elite. AI is highly adaptable in that game and it can truly be a challenge, although Spelunker Mode in 3D Dot Game Heroes is a close 2nd. Spelunker Mode would be clear and away the first, but upgrades carry-over so by the time you actually unlock the mode you have some ridiculous swords.
If we are talking about just single-player play, then its Hard-EX mode in Valkyria Chronicles for me. Its only available in the skirmish mode, but basically its an alternative set of enemy placements and resource limitations in existing skirmish maps designed to be difficult after you've maxed out classes and weapons!!! Meaning its designed to provide a challenge to players who have played through the game 2+ times already. Many times even if you know exactly where to go this mode can present a controller-smashing level of frustration.
Gauss's Piracy Uncertainty Principle: When you pirate a game, that act inherently changes the results of what is to come after your pirating. You can't make any statement with any certainty regarding what would have happened had you not pirated the game.
Gauss's Rating Rationale:
0-1: A game whose very existence is abhorrent to all things creative and intelligent.
2-4: A just plain bad game.
5-6: A game that has alot of mistakes, but is atleast playable and has some enjoyable sections. Good for a rent.
7: An average game, should be played at some point
8: A good game, should buy at some point
9: A great game, day-one purchase
10: A game that goes above and beyond the generation, its transcendent.
For me, 'MoH: Frontline' probably has the hardest hard mode i've came across. Finally beat 'The golden lion' level last Sat after around 50 tries. I had given up about 6 months ago, couldn't face it lol, but decided to give it another go. Pity it's on my old account Gonna be a sweet plat though.
Well after getting killed by the same Vorcha every time I try to get through it, I'm going to go with Mass Effect 2's insanity mode.
Is it the one with the flamethrower hiding in the corner?
To answer the OP, Catherine Hard is HARD HARD.
The exposure of the female's soft body. Whether you like it or not, being naked to the waist and the mismatch between the hard and thick jeans. The true essence is the union of girly and boyish styles.At the same time, the hand-bra forces even the current girls that lack shameful feelings to make an embarrassing pose. Depending on how it is seen, it also shows a form of eroticism by making it look like the girls are rubbing their own breasts.