When you have collected ALL the artifacts in the game the Art Gallery will become unlocked.

Drink From Canteen:
To be able to drink from the canteen hold X (tapping X takes longer). When you fill your canteen hold X.

Magical Barrier:
Press R1 to block after equipping the PaCheng.

Avoid Falling Damage:
To enter combat mode press R1 before you hit the ground. You will not sustain any damage falling.