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.
Much secret!
It probably has no use
You were hoping you would never see him again
You feel way too OP now
Heated up the water
Boing
Don't look behind you
Beep beep
Left the level
You're probably 50% done now
Flying, sort of
Improvised
Very secret!
And all I got was this lousy chest
The kids liked it
You smell so nice
Very unrealistic
Burn 'em all
Not sure if it's just a blue stone pickaxe
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
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
It feels so stable
Brings back the good old economy
Excellent plumbing work
I can fly... for a very short moment
So much industry
You are less lost
You're so attractive
Purple lines
This one will never break
Hello there!
Defeated Surprise Chest
Cage Town
Killed the ghouls
It's made of wood, it will last forever
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