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