Here is the full list of all 13 Bard to the Future achievements.
Find somewhere to pee
Satisfy the Battlebard’s curiosity
Defeat the Sorcerer
Chase the cyborg pirate without dying
Collect all the map pieces
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Beat time trial mode on all Medieval levels
Beat time trial mode on all Pirate levels
Beat time trial mode on all Ancient Egypt levels
Beat time trial mode on all Ice Age levels
Beat time trial mode on all Aztec levels
Beat time trial mode on all Gold Rush levels
Beat time trial mode on all Present Day levels