To unlock the Artworks, complete all Shaman games

After you finish the "chicken suit" part you will see two enemies. There is a red one with a shield and a bluish-gray one without. After you kill them you will see a pole with three prongs. Go to it and jump up. You will see a rock wall crumble, opening a path. After you go through the path there is a cave to your left. Swim through the water. You will find a small opening to your right with three bolder-like objects. If you break them open you will get some money to buy shaman jewelry..

Play through the game until you get to the lobster suit part. When you come out of the water, there should be a portal in front of you. Go through it and kill the three worm-like creatures that come out of the ground. Collect the Rokker gems (the small gems that appear from the monsters), and the health if need (feathers refill health). Then, turn around and go back through the portal previously exited. When you go back again, the monsters will be back. Repeat this for a lot of experience. Each time you kill the monsters you will get 33 experience points. This will work in any location that has enemies and a portal or door.