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