Here is the full list of all 30 DUSK achievements. It takes around 15-20 hours to unlock all of the achievements on Windows.
Watch the credits to the end
Complete all three episodes
Complete episode 3
Earn the 'Completionist' award in every level
Pick up a bar of soap in each level
Find Lavender's secret
Get past wave 20 in Endless Mode
Get past wave 10 in Endless Mode
Get past wave 5 in Endless Mode
Use cheats
Neutralize Chomper
Telefrag the Guardian
Reach E3MS
Complete episode 2
Find 'Wife of Intoxigator'
Open Duskworld
Reach E2MS
Complete episode 1
Find a "You aren't supposed to be here go away" sign
Find Dopefish
Kill Intoxigator while intoxicated
Reach E1MS
Find Rachael's secret
Kill an enemy by spinning your weapons
Earn the 'Untouchable' award
Beat a level on 'Duskmare'
Earn the 'Pacifist' award
Earn the 'Low Tech" award
Beat par time in a level
Earn the 'Completionist' award