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