Here is the full list of all 29 Nightmare Boy trophies - there are 10 bronze, 12 silver, 6 gold and 1 platinum.
100%
Complete the game by getting all of Aster's parts.
Complete the game.
Finish the game before anyone by defeating Balder in the room.
Expose all of the Easter eggs.
Complete the game without killing any Mongos
Buy all of the items in the store.
Discover the whole map.
Put an end to Spikey's love.
Acquire all of the skills.
Unblock all of the spells.
Kill more than 200 Mongos.
Save the game at least once.
Complete the game without saving.
Complete the game without even dying once.
Kill at least one Forest Medusa.
Open all of the chests.
Defeat Virgilio.
Save Daisy.
Save Lydia.
Save Leyre.
Save Molly.
Save Rob.
Save Dmitri.
Save Berg.
Return the ball to Adam.
Hurl a cake at 10 enemies.
Help Dani get out of prison.
Kill Virgilio and hide the truth.