Here is the full list of all 28 The Sphere of Abyss achievements.
Talk to Luna.
Buy 10 items.
Upgrade any weapon to maximum level.
Unlock all perks and skills of one charactar.
Die for the first time.
Clear Windmill Hill level on or above normal mode.
Clear Dwarf Mines level on or above normal mode.
Clear Forgotten Desert level on or above normal mode.
Clear Oracles Realm level on or above normal mode.
Clear Ice Heart level on or above normal mode.
Clear the game on normal mode.
Clear the game on hard mode.
Clear the game on abyss mode.
Clear the game within 45 minutes on or above normal mode.
Travel more than 10 kilometres.
Travel more than 50 kilometres.
Travel more than 100 kilometres.
Total time played more than 3 hours.
Total time played more than 10 hours.
Total time played more than 30 hours.
Clear Abyss level without being hit.
Unlock Brice.
Unlock Gary.
Unlock Rebecca.
Unlock A01.
Kill 1000 foes.
Kill 100 elite or mutated foes.
Kill 20 bosses.