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
Much secret!
It probably has no use
Left the level
You feel way too OP now
Flying, sort of
Burn 'em all
Very secret!
And all I got was this lousy chest
Beep beep
You're probably 50% done now
Very unrealistic
Boing
You smell so nice
The kids liked it
Beat the big guy
You feel so OP all of a sudden
He loves the ladies
Saved it from exploding
Don't look behind you
I used to get the earlier in the previous game
Much boom boom
Not sure if it's just a blue stone pickaxe
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
You were hoping you would never see him again
I can fly... for a very short moment
So much industry
You're so attractive
Beat the arena next to town
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
Bending the knee gets you further
Jump Higher!
Hit Rock Bottom
Run faster
He did all the work
You're halfway through the game already