Kill 50 aliens

Kill 100 aliens

Kill 250 aliens

Foot stomp 12 aliens

Execute 20 aliens

Kill 10 aliens with Trip Mines

Kill 15 frozen aliens

Kill 15 aliens with the monster truck

Kill 6 aliens with the forklift

Kill 10 aliens with environmental explosives

Kill 10 aliens with tossed objects

Kill 15 aliens with melee attacks while on steroids

Eat 10 pieces of food during the SP campaign

Kill 30 aliens with headshots

Drink beer while on steroids or vice-versa in SP

Kill 3 aliens at once

Get knocked down 10 times

Find and steal a piece of poo

Get hit by 10 Pregnator bombs

Shoot down 20 alien fighters

Look at every page of a calendar in SP

Put a Trip Mine on a live alien

Blow up 5 enemy gunships or dropships

Win air hockey with a score of 7-0 in the strip club

Earn a 1,000,000 pinball score in SP

Drink a beer in SP

Take steroids in SP

Use a Holoduke in SP

Doodle something on the whiteboard in SP

Discover all ego cap rewards

Carry the gold pistol through the whole SP campaign

Complete the SP campaign on Easy Difficulty

Complete the SP campaign on Normal Difficulty

Complete the SP campaign on Hard Difficulty

Complete the SP campaign on Insane Difficulty

Watch the credits all the way through

Find all 3 helmets in the SP campaign

Listen to all phone messages

Drink all of the beers in the strip club

Kill all of the catfish in the underwater level

Shoot down the blimp above the stadium

Knock out the talent at the talk show

Win a game of Alien Abortion in the strip club

Unlock the secret closet at the end of the Forkstop

Defeat the Cycloid

Defeat the Battlelord in Las Vegas

Defeat the Alien Queen

Defeat the Battlelord on the Hoover Dam

Defeat the Octaking

Defeat the Energy Leech