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.
Have one Knight defend for another Knight.
Reflect 100 damage from a single attack.
Find a rare item.
Sell 100 items.
Slay 500 enemies.
Enter a battle in the Arena.
Complete dungeon level 100.
Complete 50% of the bestiary.
Slay 10 bosses.
Discover and explore an alternate path in the dungeon.
Complete your first dungeon trip.
Complete dungeon level 250.
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.
Complete 100 levels in one trip.
Win a battle by only defending.
Complete 50 levels with only one Soda Junkie.
Hope you're hungry.