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