Here is the full list of all 43 Leveling up girls in another world achievements.
Let Ayumi convince you to train three times
Is this the Happy Ever After?
Is she really defeated?
Does a fair maiden's kiss work?
Get everything to make the potion
And she calls herself a demonprincess?
Not a real threat, is she?
And she's a demon princess?
Think twice, before you say "I wish"
Find a strange girl manifest from the lamp.
Watch Tomoya fall for a classic slime trap
Find Iori bathing in the river
Let Tomoya use Sachi as her doll
Complete ten different quests from the board
That's a weird way of demanding payback.
Meet Isabelle's familiars
Learn about Mikako's strength
Spend 10.000.000 Gold in the shop
Spend 1.000.000 Gold in the shop
Speed up your recovery.
You didn't sleep for two months, did you?
Find Ayumi standing in front of you, wearing a ... school uniform?
Meet Hitomi again.
Isn't it dangerous to feed an assassin?
Let Sachi hold your body weight.
Complete your first sidequest
How to tame an assassin
Meet Sachi for the first time... uuuh the most deadly assassin.
Every Adventure needs a break!
Encounter Hitomi in the castle
Encounter Iori, the Elven Archer
Meet an old "friend" with a bunny tail and ears
Find out about the true inention of Benedict and his gang
Find Ayumi after she ran off
Learn about the girl's prickles.
Spend 100.000 Gold in the shop
Encounter Tomoya at Moon Village
Wake up after your first night in Aporia
Don't let Fubuki manage your money.
Max out a skill for a girl
Get your first skillupgrade
Clear your first dungeon
It's been five years, welcome back