Here is the full list of all 21 Action Henk achievements.
Jump over the barrier.
Ragequit the game during a level.
Die 100 times.
Publish a level to the Steam Workshop.
Beat Kentinator's Challenge.
Beat Cedar's Challenge.
Defeat Kentony's challenge.
Beat Neil's Challenge.
Fall into the lava.
Defeat Betsy's Challenge.
Beat Action Henk in the City.
Earn a Bronze medal on all levels.
Earn a Silver medal on all levels.
Earn a Gold medal on all levels.
Earn a Rainbow medal on all levels.
Beat all bonus levels
Challenge a friend to beat your score.
Beat 99% of all players on a level.
Win a multiplayer match.
Press reset over 9000 times.