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