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.
Destroy two generators before entering Vectron.
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.
Complete the game in less than 2 hours, 30 minutes.
Complete the game without getting killed once.
Crush 10 enemies with falling blocks.
Find and sell 8 Trashium ores at the same time.
You found Archaea!
Find all secret areas in the caves.
Reach the bottom of the world.
Destroy a laser box.
Maximize all upgrades.
Immortalization of a destructible steambot.
Defeat 10 mecha trilobites before they wake up.
Defeat a turtle submerged in water.
Find and sell 16 Dark Matter ores at the same time.
Buy from all of Tumbleton's shops.
You found Vectron!
Find and sell 8 Uranium ores at the same time.
Defeat 10 shiners before they wake up.
You found the Old World!
Defeat 10 trilobites before they wake up.