Here is the full list of all 58 Forget Westbury Falls: Disc One achievements.
Escaped the lab.
Defeated Lee Cotter and found a Director.
Defeated Francis "Friendly" Angelou.
Defeated Gabriel Hart and cleared the History of Combat Battle Tower.
Defeated Robert Marlon with Elfriede.
Defeated Desmond Wallace and brought down the Financiers.
Defeated the Man in Black.
Defeated Wesley in Edith's flashback.
Defeated the Formless...right?
Defeated the World Swallower with April's help.
Defeated the Man in Black again.
Defeated Edith Lane.
Saved Laura Dagny.
Defeated Marley Hancock and completed Act One.
Defeated Breahin.
Defeated Jack Fairland.
Defeated Beff Jezos' final form.
Defeated Leland Cole.
Defeated Rufus Schrader.
Defeated Andre Madsen.
Defeated Devadas.
Defeated Biker Roose.
Defeated Donn Fernand.
Defeated Mad Hazel.
Defeated Dominic Earl.
Defeated Robert Marlon with Newman and Maya.
Defeated Mastery Jack.
Defeated Father Rory.
Defeated Casey North.
Saved Dominic Earl.
Defeated Henadad and completed Act Two.
Defeated Andre Madsen in the underground rematch.
Defeated Roy Damien.
Defeated the Sealed Spirits.
Defeated the Blightfish.
Defeated Hunt.
Defeated Abaddon.
Defeated Samuel "Lucky" Crawford.
Defeated Saul Donovan.
Defeated Elfriede and Laura Dagny.
Defeated Saul Donovan a second time.
Defeated Arthur Wilton. (You're friends again, though.)
Defeated (and recruited) Abaddon in the Dead Drain.
Defeated Samuel "Lucky" Crawford and Elfraud.
Defeated Saul Donovan a third time. Is it too late...?
Saved Saul Donovan and completed Disc One.
Collected all asterisks in Disc One.
Collected all Bond Hearts in Disc One.
Found Jake!
Found Waffle Chef in the Underground!
Got the Dog Ending.
Defeated the Hypogean Monarchs.
Gave Maya the DRUNK and STONED status effects at the same time.
Rescued all dogs in Disc One.
Cleared "An Inverted World" in the dancing minigame.
Defeated Breahin, the final form of Beff Jezos, Jack Fairland, Roy Damien, the Sealed Spirits, and the Hypogean Monarchs on Midnight difficulty, all on the same playthrough, without dying once.
Defeat the roaming car miniboss for each act at least once.
Defeat every form of Roose available in Disc One.