Here is the full list of all 27 Max: The Curse of Brotherhood achievements.
Can't Touch This
You found the first piece of the lost Amulet.
You destroyed 5 of Mustacho's Evil Eyes. That'll teach him.
You used the magic marker 25 times.
And just in time for tea! (Reached the old lady in under 5 minutes)
You defeated Mustacho and saved your brother!
You tamed the Spikester! ...Lucky you.
Time Marches On. (Rang a bell)
You stole back your kid brother like a boss!
You drew 200 branches.
You drew 200 vines.
You drew 200 water streams.
Guts and Glory
One Sea of Sand, 2 Earth Pillars, 3 drawings - piece of cake.
You defeated Mustacho without dying even once!
You found and assembled the entire Amulet for the Old Lady!
It's all in the fingers and fiery balls of death.
No Evil is safe from you and your Grabby Hands.
What goes around, comes around. Right in your face.
You lit 15 enemies on fire. Oh the things One does for brotherly love.
Up you go.
You found and assembled 6 pieces of the lost Amulet.
You found and assembled 12 pieces of the lost Amulet.
You destroyed 25 of Mustacho's Evil Eyes. Consider his surveillance network impaired.
You destroyed 50 of Mustacho's Evil Eyes. His control is diminishing!
You didn't die in Death By Lava.
You escaped the Beast without dying!