Here is the full list of all 19 Gang Beasts achievements. It takes around 1-2 hours to unlock all of the achievements on Windows.
Concuss an enemy with a diving headbutt
Break the cables supporting an elevator without falling on the elevators stage
Collide with the seating and the railings on the ring stage
Climb onto the roof of a truck on the trucks stage
Escape from the water on the buoy stage
Escape from the incinerator hazard on the incinerator stage
Escape from a grinder hazard on the grind stage
Customise a character on the character customisation screen
Get inside a shipping container on the containers stage
Pass through the orange chute on the girders stage
Defeat an enemy wave in the waves game mode
Get inside a truck on the trucks stage
Concuss an enemy with a diving kick
Win a game of football without the opposition scoring in the football game mode
Climb to the highest section of the buoy on the buoy stage
Break the cables supporting a container without falling on the containers stage
Break the cables supporting a gondola without falling on the gondola stage
Pass through three road signs on the trucks stage
Break the stairs on the towers stage