Destroy All Humans!

When you are in the form of another person, to make you brain juice meter go down, read other people's thoughts.

Stand in an open area on any level and walk forward. Keep decreasing your speed until you eventually begin walking in place.

To gain additional DNA from Brain Extractions, complete all of the main missions.Example: Instead of gaining 10 DNA, you will gain 15 DNA.

The Password you say to the ferryman to get him to move the barge is Marlyn.

Allow the game to idle. Eventually the screen will turn black and white and elevator music will play in the background.

After getting out of your UFO, aim at a human and press Circle. When you have changed into the human, the bar on the top left corner of the screen will go down. When it is all gone, you will change back into an alien. If you want to remain human, turn into a human and while walking around, scan other humans or animals to make the bar on the top left corner stay up.

Collect all Probes in Santa Modesta.

Collect all Probes in Rockwell.

Complete Attack of the 50ft president.

Collect all Probes in Turnipseed Farm.