Here is the full list of all 35 Neon Abyss achievements.
Made deals with Smirk Co. 99 times.
Unlock 6 Characters.
Fished 10 times in fishing room.
Opened 999 locked chests.
Acquire 10 heart containers in a single run.
Stepped on worms 999 times.
Jump in the air for 10 times before landing.
Jumped 9999 times.
Complete a run without picking up any hearts.
Defeat Goddess of Illusion.
Found 5 secret rooms in a row.
Completes the Piano challenge 10 times.
Defeat God of Violence.
Defeat God of Machines without getting hurt.
Defeat the God of Electricity.
Defeat God of Machines.
Acquire 10 shields in a single run.
Get 50 eggs in a single run.
Defeat God of Darknet.
Successfully hatch eggs 5 times in a row.
Death is another beginning.
Get killed by your bombs.
Failed to hatch eggs 5 times in a row.
Get killed by environment damage 9 times.
Died in the Abyss 99 times.
Found 99 secret rooms.
Entered the abyss for the 999th times.
Unlock Abyssal difficulty.
Get killed by your own bomb while in the air.
Played the Roulette machine 99 times.
Defeat Athena in Abyssal Difficulty.
Complete a run without losing any hearts.
Empty 4 shops in a single run.
Defeat Argus without picking up any items.
Dance in the bar for 30 minutes.