"Ok, come on, you knew this game was going to be on here. The game is brutal, but fair. Since the enemies are always in the same places, it's more a matter of practice than sheer difficulty, but it's quite fun and worthy of making this list."
"Another obvious title. But it doesn't get truly hard until your unlock the higher difficulties -- until then, again, it's just a matter of practicing (hint: use "Flying Swallow" or "Izuna Drop"). Obviously, this applies to all versions of the 1st Ninja Gaiden game."
"A spin-off of the Disgaea series, this game shifts from SRPG to intense 2D platformer. Unlike Super Meat Boy, Prinny has a variety of attacks available to him (slash, air slash, hip pound), so expect more combat."
"Assuming you don't play on Easy, this game provides quite a challenge. Admittedly, the "Undo" button removes much of the difficulty of the puzzles, but don't get cocky -- on "Hard", not only do the puzzles become more challenging, but the game also removes the Undo feature."
"A truly great turn-based RPG, but also one of the most unforgiving. Expect most bosses (especially early on in the game) to wipe the floor with you on the first attempt. The trick here isn't just to level grind, but rather to set up your party correctly for the fight."
"To clarify, the main story isn't terribly bad -- however, the alternate "Snow Queen" storyline is brutal. Each tower you enter has its own way of making your journey more difficult. Add to that a time limit for each tower and the game suddenly becomes much more challenging than its main story."