Here is the full list of all 31 Dokuro trophies - there are 16 bronze, 9 silver, 5 gold and 1 platinum.
Use red chalk successfully
Collect 25 coins
Collect 10 coins
Use white chalk successfully
Collect your first coin
Earn all other Dokuro trophies to unlock this platinum trophy
Collect all coins
Complete all areas in a total of 250 minutes or less
Defeat 100 monsters in Skeleton Form
Defeat 1000 monsters in Hero Form
Complete stage 14 without taking any damage
Light 4 torches with a single red chalk
Complete all areas in a total of 350 minutes or less
Fall from a great height
Collect 135 coins
Collect 120 coins
Collect 100 coins
Complete stage 11-5 without being discovered once
Complete all stages
Defeat the Dark Lord without taking any damage
Complete stages 1 to 4
Complete stages 5 to 8
Complete stages 9 to 11
Complete stages 12 to 15
Collect 50 coins
Collect 75 coins
Pick up the Princess 200 times
Die 100 times
Successfully deflect boomerangs 100 times
Let the princess get knocked out 100 times
Use blue chalk successfully