Favorite hard game?

I'm talking balls off the walls nuts in difficulty, stuff like Devil May Cry 3, Super Monkey Ball 2, Dark Souls. name em and give some reasons why you love those games, for instance, I'm a huge fan of Devil May Cry 3, it's difficult, brutal at times, and kicks you when you're down, but I made it through and enjoyed myself.

The original Castlevania games. They are some of my favorite games on the system and their soundtracks kick so much ass.

Vanilla DMC 3. Where Normal = Hard and easy mode was normal. God I played the shit out of that version...good times :)

A lesser known title, but Rune Factory 4. The enemies start out weak, but the post game dungeon Rune Prana which continues the story, and the optional dungeon known as the Sharence Maze which contains the strongest bosses of the game, are extremely challenging. You have to grind to about level 500 to have a chance at even damaging some of the stronger ones in the Sharence Maze, and they're still likely to KO you in one shot. Even Ventuswill can get knocked out quickly by them, and her HP eclipses your own about a thousand times over.

Touhou 11. I've already beaten the previous 5 touhou games on normal in my crusade to conquer them all, but Touhou 11 is a different beast entirely. Its gonna take me quite some time till I can get comfortable with it to even try to beat and 1cc it :(

Ninja Gaiden Sigma The first one in the series was by far the most difficult, and also the most rewarding. Getting all the collectables is well worth your time as you get an awesome weapon for it, and there is also another cool weapon you can get if you put in the time to make it. All the fights require proper timing and strategy, just flailing around mindlessly will get you nowhere. Definitely a challenge worth taking if you are up to it.