Here is the full list of all 27 Max: The Curse of Brotherhood achievements worth 400 gamerscore.
Find the first piece of the amulet
Reach the Old Lady in under 5 minutes
Solve the last puzzle in Sea of Sand by only creating 3 Earth Pillars
Find and destroy 5 of Mustacho's Evil Eyes
Ride the Spikester for at least 10 seconds
Find a bell and ring it, a lot
Kill a Bomber with his own bomb
Complete a level without dying
Light 15 of your enemies on fire
Draw 200 branches
Draw 200 Vines
Draw 200 Water streams
Make 5 critters explode and survive
Kill two enemies with one shot
Destroy all of Mustacho's Evil Eyes
Recover all the pieces of the lost Amulet
Rescue your brother without killing him
Defeat Mustacho without dying
Use the magic marker 25 times
Recover 6 pieces of the lost Amulet.
Recover 12 pieces of the lost Amulet.
Destroy 25 of Mustacho's Evil Eyes.
Destroy 50 of Mustacho's Evil Eyes.
Don't die in Death By Lava.
Complete Sliding Escape without dying.
The box is the key to the wall.