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.
Heated up the water
It probably has no use
Much secret!
Left the level
The kids liked it
You feel way too OP now
Flying, sort of
Very secret!
Burn 'em all
Beep beep
Boing
Don't look behind you
Excellent plumbing work
You were hoping you would never see him again
And all I got was this lousy chest
Beat the arena next to town
You smell so nice
Improvised
You're probably 50% done now
Very unrealistic
You are less lost
Beat the big guy
You feel so OP all of a sudden
Saved it from exploding
He loves the ladies
I used to get the earlier in the previous game
Much boom boom
Lifting weights
Gold Module
You're a criminal
Bzzz bzzz
Broke into the bank
Get an accountant
Not sure if it's just a blue stone pickaxe
Made it to the 2nd floor
Brings back the good old economy
I can fly... for a very short moment
So much industry
It feels so stable
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