Here is a short guide on how to get all hidden achievements in Return to abyss.
Note: Thanks to @Eizen from the discord for compiling this from the forums, and for letting me post it with more details. You’re the best!
Narrow Escape
Win the battle when your HP is below 10.
Reincarnation
Die for 100 times in Abyss.
Dangerous Driving
Forge a blue Wildfire 03 while having 2 drinks active.
(Don’t worry, the drinks don’t break this achievement!)
Dionysus
Master 12 drink formulas.
Take a Break
Do not move for 120 seconds at the start of the battle, during which you cannot die (no revives!)
(This is really easy to do with the lightning ball character in zone 1, as soon as you unlock her.)
Wrecking Ball
Destroy the Lava Ball of Demon Lord Samuel (Zone 1 boss) in Hell Surface (Zone 1.)
Home Run
Simultaneously repel and defeat the Fusion/Cancer of Humanity (Zone 2 boss) while it’s rolling.
Karma
Let tentacles whip Baron Assac (Zone 3 boss) to death in Evernight Marsh.
Facehugger
Get snatched into Desperate Shadow (Zone 4 boss)’s body and kill it from inside in Inner World (Zone 4).
Matador
Avoid the Leviathan (Zone 5 boss) bite attack 3 times (in one run.)
Abyss Lone Fighter
Win an abyss without picking up a treasure chest.
