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