Here is the full list of all 22 Bardbarian achievements. It takes around 10-12 hours to unlock all of the achievements on Windows.
Do all the things! 100% Completion.
Unlock the mythical 4th party slot.
Go as fast as you possibly can. (Hint: Upgrade + Song)
Complete the entire campaign from start to finish without dying.
Fact: There are 1609 meters in a mile.
Post a score in the Day 2 Insane Mode leaderboard. The most exclusive of all leaderboards.
Complete the "night" chapter.
Send 2500 enemies to their grave.
Complete the "evening" chapter.
Loot 100,000 gold from the corpses of your fallen enemies.
Reach 3000m in Escape mode, and he's yours.
Start a new game in Insane Mode.
Complete the "noon" chapter.
Upgrade a unit to MAX level.
Waltz into Wave 10 and rescue him from that Fire Golem.
Something's cooking on the title screen.
Play and submit your best time for Survival Mode.
Last for 3 minutes in survival mode.
Appears randomly in Survival mode. May luck be with you.
Complete the "morning" chapter.
Don't get hit!
You look lonely, have you considered a pet to keep you company?