Here is the full list of all 34 ICEY achievements. It takes around 4-5 hours to unlock all of the achievements on Windows.
Defeat TrinityEven after her memories were mixed with another's, Trinity still tried to prevent the birth of the Chosen One. That was, of course, futile.
Defeat DahalOnly in a virtual world is such a thing possible... To mix two beings' memories... Because of this, Dahal short-circuited.
Destroy the background music player
Keep trying to go left in the "extra area"
Learn the name of God
Do not wake up ICEY
Ignore the narrator and enter Emberville before the gate closes
Jump into sewage 3 times
Do not activate the photon bridge and jump 3 times into the ravine
And in the dark of night, the unfathomable Black Star rises
Defeat JudasJudas had long ago given up his struggle. As he ascended the Clock Tower, the Black Star rose once more.
Select "Not Ready" before the final battle
Do not kill Dahal's self which lives within Trinity
Defeat IdeonIdeon's self was slowly destroyed through the process of never-ending reincarnation, leaving him even more vulnerable to Judas' manipulation.
Break open Pandora's box
Confront the Yellow King in the monitor room
Defeat JackWhile Jack's faith is unwavering, being banished to the furthest corner of the world left him unable to even come close to the Chosen One.
Earn sponsorship for the game
Encourage the narrator to meet the tip of a bullet
Defeat CarlosCarlos was fed up with the constant sacrifice of his self in each reincarnation. His solution? Kill and replace the Chosen One.
Enter level "Shio"
Defeat ParkerParker, betrayed by Judas, retreated with no conscience to the dark corners of the metro.
Discover the truth of ICEY's birth
Defeat ThorThor understood Judas' ultimate goal, and paid the ultimate price of splitting his self to serve Judas.
Witness secrets of development in the "Archive Room"
Defeat GorgerGorger was a simple resident of Ultimopolis that sacrificed himself to Judas without regret... or any other feelings.
Finish the story in the "Totally Empty Room"
Earn a silver trophy in the "Totally Empty Room"
Earn a bronze trophy in the "Totally Empty Room"
Wait for a few minutes in the "Totally Empty Room"
Enter the real "game" with the narrator
Defeat TrinityTrinity could not stop this cycle, nor can she ever stop the wheel of reincarnation from spinning.
Earn all trophies
Witness the birth of ICEY's self-awareness