Number one difficulty:
To unlock Number One difficulty, beat the game on the default difficulty setting.
Treasure gallery:
To unlock a treasure gallery, complete story mode.
Display game stats:
To display game stats, press both analog sticks at the same time.
How to defeat Brother 6:
To easily defeat Brother 6 with the flamethrower, start by either running a circle around him until he stops shooting fire or hits you with the fire. If he hits you, he will laugh and give you an opportunity to attack. Use the Dashing Slash (Square) to stun him. Next, use the Square(4) combo until he shoves you away. After hitting the ground, immediately use Dashing Slash again. If done fast enough, you will interrupt his attack and stun him. Repeat the combo on him, then repeat the entire process through the rest of the phases.
How to defeat Daimyo:
To easily defeat Daimyo, you will know that he is about to do a big attack when his weapon sparkles. Time your blocks to parry his attacks. When he is open, use any desired combo until he back flips away. Repeat this until he has been defeated.
How to defeat Sword Master:
To easily defeat Sword Master, time your blocks to parry his attacks and leave him open. You will know that he is going to use a big attack when his weapon begins sparkling. Use any combo until he begins blocking. After you have locked swords with him twice, he will become faster and stronger. Continue to parry him and combo back if you are skilled at timing your moves. Otherwise, Focus Dodge and attack.