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