Here is the full list of all 54 Lennas Inception achievements.
Beat the "3 Hearts" challenge
Get one of every item
Call the developer from in-game
Use a potion to skip Lance's death cutscene
Confuse an NPC by naming yourself Lance
Double your money in a single trade at the bank
Beat the "All Dungeons" challenge
Beat the "Bomber" challenge
Beat the "Arsonist" challenge
Beat the "I AM ERROR" challenge
Beat the "Sniper" challenge
Beat the "Daily Seed" challenge
Defeat Delvin without killing him
Save the Elder
Save Lance
Play Tombs & Tentacles
Blow up a rock before you obtain the bombs
Beat the "1 Dungeon" challenge
Beat the "Reflex Mode" challenge
Play a challenge
Play local co-op with a friend
Max out your heart meter
Master the Hallucination Tunic
Get the "Perfect" ending
Defeat the Chairman without killing him
Defeat a boss without killing it
Get the "Catastrophe" ending
Bring powered-up Henrietta to the fight with Delvin
Cross the world wrap
Empower Henrietta
Find a tomb under a gravestone
Access a dungeon without defeating the boss in the dungeon before it
Kill a Whirligig
Get the "Sacrifice" ending
Order a pizza
Get the Book of Changes
Uncover the whole overworld map
Get the Binoculars
Get the Error Log
Get the Beta Cup
Drop a hallucination potion on yourself
Drop a beer potion on yourself
Get the Patent
Get the IOU
Do a lightning attack with the Tungsten Sword
Do a spin attack with the Damascus Katana
Melt ice before you obtain the lighter
Earn Paige's affections
Find a cave within a cave
Unlock Paige as a companion
Get the Police Report
Unlock Shadow Lenna
Kill a boss for the first time
Beat the "0 Hearts" challenge