Here is the full list of all 23 Ice Demon achievements.
Reach Belt Rank title Yellow.
You died. Learn from your mistakes and grow stronger as a result!
Reach Belt Rank title Orange.
Reach Belt Rank title Green.
Reach Belt Rank title Blue.
Reach Belt Rank title Purple.
Reach Belt Rank title Red.
Reach Belt Rank title Brown.
Reach Belt Rank title Black.
Score 100 kills on Mt. Gunpowder.
Score 100 kills on Gunpowder Cave.
Score 100 kills on Carina Ruins.
Score 100 kills on Technospace.
Score 100 kills on Demon World.
On Expert Mode, score 100 kills on Mt. Gunpowder.
On Expert Mode, score 100 kills on Gunpowder Cave.
On Expert Mode, score 100 kills on Carina Ruins.
On Expert Mode, score 100 kills on Technospace.
On Expert Mode, score 100 kills on Demon World.
Score 60 kills on Bestiary Mode.
Stay alive for two minutes on Survival Mode.
Score 100 kills on Heaven Mode.
Kill a Chibeara on difficulty level 7 or higher.