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
Beep beep
It probably has no use
Left the level
Burn 'em all
You feel way too OP now
Flying, sort of
Very secret!
Boing
You're probably 50% done now
Very unrealistic
The kids liked it
Beat the arena next to town
And all I got was this lousy chest
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
Don't look behind you
Saved it from exploding
I used to get the earlier in the previous game
Much boom boom
Lifting weights
Improvised
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
You were hoping you would never see him again
So much industry
You're so attractive
You are less lost
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
You smell so nice
Much secret!