Here is the full list of all 22 Flynn: Son of Crimson achievements.
Quickly skip Bohrin's dialogue.
Have a throwable rock bounce on an enemy 5 consecutive times without touching the ground.
Have an enemy frozen, burned and zapped simultaneously.
Using the sword, pogo-bounce on 4 separate enemies without touching the ground.
Defeat a training dummy in Sanctia.
Completed all levels, acquired every relic and learned every skill.
Defeat Zealock
Find, collect and sell all 20 relics to Yombal.
Defeat Imbra the Shadow Sorceress.
Acquire every skill from Loretta.
Complete the 6 challenge stages.
Find Bax in 4 separate locations.
Perform a full plummet combo with any Crimson weapon.
Chain zap 7 enemies with lightning magic.
Defeat Xellios the Toxic Marksman.
Defeat Kravios the Aquatic Voltknight.
Defeat Rozia for the final time in the Desolate Woods.
Starting with an uppercut, perform a full aerial combo with any Crimson weapon.
Defeat Bora the Whirlwind Assassin.
Acquired your first skill.
Find and collect a golden relic.
Set out on an adventure with your beloved friend, Dex.