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