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