Here is the full list of all 21 Action Henk achievements.
Beat Kentinator's Challenge.
Beat Cedar's Challenge.
Defeat Kentony's challenge.
Beat Neil's Challenge.
Defeat Betsy's Challenge.
Fall into the lava.
Publish a level to the Steam Workshop.
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.
Ragequit the game during a level.
Beat 99% of all players on a level.
Jump over the barrier.
Win a multiplayer match.
Press reset over 9000 times.
Die 100 times.