Here is the full list of all 27 Duke Nukem 3D: 20th Anniversary Edition World Tour achievements worth 1,000 gamerscore.
Complete "Alien World Order" on any difficulty.
Find Sam in "Mirage Barrage".
Kill a Firefly Trooper while it's flying small.
Use the hookah in High Times.
Complete "The Birth" on any difficulty.
Find Luke in the Level "Lunar Reactor"
Kill 10 bad guys in 10 seconds while on steroids.
Find 70 secret areas.
Burn 50 bad guys to death.
Use the Incinerator
Carry all weapons with ammo at once.
Finish any level on "Damn, I'm Good" difficulty.
Kill 5 bad guys with one shot.
Finish the "Hollywood Holocaust" level in under 3 minutes.
Use a cheat code.
Complete "Shrapnel City" on any difficulty.
Finish a secret level.
Kill 1000 enemies.
Complete "Lunar Apocalypse" on any difficulty.
Step in a pile of excrement.
Step on 40 enemies after using the Shrinker on them.
Kill every enemy on a level.
Complete "L.A. Meltdown" on any difficulty.
Find the Doomguy in the Level "Death Row"
Tip an exotic dancer.
Listen to Developer Commentary (Use at least one trigger).
Find a secret area.