Here is the full list of all 31 Dokuro achievements.
Collect 10 coins.
Use white chalk successfully.
Collect your first coin.
Unlock all achievements.
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 25 coins.
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 red chalk successfully.
Use blue chalk successfully.