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