Here is the full list of all 53 Supraland Six Inches Under achievements. It takes around 15-20 hours to unlock all of the achievements on Windows.
You're probably 50% done now
Don't look behind you
Improvised
The kids liked it
Very unrealistic
Beat the big guy
You feel so OP all of a sudden
He loves the ladies
Saved it from exploding
I used to get the earlier in the previous game
Much boom boom
And all I got was this lousy chest
You smell so nice
Not sure if it's just a blue stone pickaxe
Beat the arena next to town
Lifting weights
Gold Module
You're a criminal
Bzzz bzzz
Broke into the bank
Get an accountant
Made it to the 2nd floor
You are less lost
It feels so stable
Brings back the good old economy
I can fly... for a very short moment
So much industry
You're so attractive
Purple lines
This one will never break
Hello there!
Defeated Surprise Chest
Cage Town
It's made of wood, it will last forever
Killed the ghouls
Jump Higher!
Bending the knee gets you further
Hit Rock Bottom
Run faster
He did all the work
You're halfway through the game already
Heated up the water
Excellent plumbing work
You were hoping you would never see him again
Very secret!
Flying, sort of
Beep beep
You feel way too OP now
Burn 'em all
Boing
Left the level
It probably has no use
Much secret!