Here is the full list of all 45 The Last Hero of Nostalgaia achievements.
Received the Spirit's blessing.
Defeated The Grinder.
Defeated Gnom.
Defeated Wunderschonenburg.
Defeated The Narrator.
Defeated The Arena.
Defeat The Spirit of Heroism.
Defeat Mercucio.
Defeat The Reservoir of Pain.
Claim your throne.
Give yourself back to Nostalgaia.
Give The Maiden's gift to The Innocent.
Give The Reservoir's gift to The Innocent.
Complete Lady Sco's questline.
Complete Nameless Nhero's questline.
Complete Vengence's questline.
Complete The Innocent's questline.
Complete The Reservoir of Pain's questline.
Complete Blade The Bold's questline.
Complete the story in under 5 hours.
Complete the story without summoning other players or NPCs.
You died.
Have a train kill an enemy in Start of Sequence.
Drop 5 levels worth of memory in a single death.
Get an Achievement.
... In the Rehabilitation Pits and all I got was this lousy achievement.
Look up an achievement online.
Achievement not found.
Level up five times in a single beacon visit.
Perform 20 backstabs.
Perform 20 repostes.
Perform 20 rebuffs.
Collect every piece of armor.
Collect every rune.
Collect every Spell.
Fully upgrade any weapon.
Remember every relic.
Unburden every item.
Level up at The Reservoir of Pain.
Collect all Martyrdom Penalties.
Defeat Eve
Defeat Luvanni's Anger
Defeat The Adversary
Another Shirt!?
Remember all relics in The Rise of Evil DLC