Here is the full list of all 24 Soda Dungeon achievements. It takes around 60-80 hours to unlock all of the achievements on Windows.
Purchase all basic sodas.
Complete dungeon level 250.
Have one Knight defend for another Knight.
Complete 100 levels in one trip.
Find a rare item.
Sell 100 items.
Complete dungeon level 100.
Complete 50% of the bestiary.
Slay 500 enemies.
Slay 10 bosses.
Enter a battle in the Arena.
Discover and explore an alternate path in the dungeon.
Complete your first dungeon trip.
Complete dungeon level 500.
Complete dungeon level 750.
Complete dungeon level 1000.
Find a legendary item.
Complete 100% of the bestiary.
Steal essence from an enemy.
Inflict burn, sleep, poison, and confusion on one enemy.
Win a battle by only defending.
Reflect 100 damage from a single attack.
Complete 50 levels with only one Soda Junkie.
Hope you're hungry.