Here is the full list of all 24 SteamWorld Dig achievements. It takes around 10-12 hours to unlock all of the achievements on Windows.
Dig out 15000 tiles.
Maximize all upgrades.
Complete the game with more than 150 orbs collected in total.
Get all four gold stars in the same playthrough.
Complete the game with more than 20000 gold collected in total.
Find all secret areas in the caves.
Find and sell 8 Uranium ores at the same time.
Complete the game in less than 2 hours, 30 minutes.
Complete the game without getting killed once.
Destroy a laser box.
Defeat 10 mecha trilobites before they wake up.
Find and sell 16 Dark Matter ores at the same time.
Reach the bottom of the world.
Crush 10 enemies with falling blocks.
Destroy two generators before entering Vectron.
Defeat 10 shiners before they wake up.
Defeat 10 trilobites before they wake up.
Immortalization of a destructible steambot.
Buy from all of Tumbleton's shops.
Defeat a turtle submerged in water.
You found Vectron!
You found the Old World!
Find and sell 8 Trashium ores at the same time.
You found Archaea!