Here is the full list of all 35 One Step From Eden achievements.
Beat the game with every character
Kill a hostage with the Devour spell
Cover the entire field in flames
Cast 10 Jams in one battle
Kill the last enemy with the Fadeaway spell
Have 0 Max Mana
Kill Gunner or Shiso with a Slashfik spell
Have over 200 cardtridges in your deck
Beat the game without taking any spells
Beat the game without collecting any Artifacts
Beat Serif and get sent back
Have at least 16 broken tiles at the same time
Defeat tier 4 Reva
Have over 9,999 Shield
Execute Serif
Reach the Gate
Defeat tier 4 Selicy
Defeat tier 4 Terra
Defeat tier 4 Violette
Have 1 Spell in your deck
Defeat tier 4 Shiso
Defeat tier 4 Hazel
Get a Calamity spell
Win a boss fight with 1 HP
Spare Terrable
Defeat tier 4 Gunner
Defeat tier 4 Saffron
Defeat tier 4 Shopkeeper
Upgrade the same spell 4 times
Have 8 pacts at the same time
Win a battle without using a Spell or Weapon
Destroy a Self Defense hazard
Have a spell from every Focus in your deck
Beat Hell Mode 14
Execute Terrable