Here is the full list of all 42 Ghost Song achievements.
Help your friends escape.
Complete the game on Original difficulty.
Defeat a Big Bot.
Do a killer Painwheel juggle.
Show off with flowers.
Obtain many modules.
Find Charley.
Receive a special gift from Molly.
Once again, help to repair Gambler.
Fully repair Gambler.
Obtain many weapons.
Help Gili.
Visit The Cut Machine.
Defeat Kellunhelk.
Defeat Henriette again.
Get to know Saymund.
Say goodbye to Mutt.
Push the large piece of junk down the hill.
Have a chat with Relic.
Reach Mabec.
Continue to assist in the repair of Gambler.
Defeat Vek.
Locate many Big Bots.
Spend time with Pasha.
Bring a third part to Gambler.
Defeat Old Singer.
Reach level 30.
Defeat Elsom.
Obtain many Healing Cores.
Help to repair Gambler again.
Heal yourself many times.
Defeat Henriette...
Help to repair Gambler.
Defeat Kika.
Defeat many enemies.
Defeat Dolly.
Arrive at the crash site.
Destroy many innocent creatures.
Get to know the crew.
Destroy many Roslock creatures in the pit.
Complete the game without dying.
Finish the game in under 3 hours.