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