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!
Heated up the water
It probably has no use
Left the level
You feel way too OP now
Flying, sort of
You were hoping you would never see him again
Very secret!
Beep beep
Burn 'em all
You're probably 50% done now
Very unrealistic
Boing
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
Improvised
Excellent plumbing work
And all I got was this lousy chest
Not sure if it's just a blue stone pickaxe
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
I can fly... for a very short moment
So much industry
You're so attractive
You smell so nice
You are less lost
Beat the arena next to town
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
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