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