Here is the full list of all 22 Devolverland Expo achievements. It takes around 1-2 hours to unlock all of the achievements on Windows.
Don't get caught by those frickin' laser beams
Defeat the Boss
Watch the Olija trailer
Watch the Weird West trailer
Collect all the hidden pieces for the third unannounced game
Collect all the hidden pieces for the second unannounced game
Watch the Blightbound trailer
Watch the Serious Sam 4 trailer
Dare to don the Glove of Power (mkII)
Knock over all the walking Fall Guys
Watch the Shadow Warrior 3 trailer
Watch all the trailers!
Check out all the Devolver game booths
Watch the Fall Guys trailer
Collect all the hidden pieces for the first unannounced game
Break the code to the ventilation system
Watch the Carrion trailer
Pick up an access pass for the expo
Unlock the door up to Security
Take out a security drone
Pick up your essential T-shirt launcher
Rewire the electrics to get in