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