Area 51 Hat

Get to level 3-1.

Blond Hair

Beat the final boss on Hard mode.

Curly Hair Wig

Blow up the Fish are like plants building in level 1-5.

Dimond tirera

Beat level 2-2 on Hard.

Extra life

When there is a flower in the ground dig next to it and you will get a life.

Hidden Hats

In the Options Menu, where you can rename your alien, use the following names to unlock hidden hats for the 2 player game:

* cletus
* april
* superfly
* goodman
* grrl
* abe
* princess
* dandy

Jouster hat

Beat level 3-4 on Hard.

Level 3-4: Extra lives

After fighting the Boss (giant green robot with the eye and a fork and knife) and his life reaches zero, he will start exploding. Continue shooting at his eye. He will just continue exploding as long as you shoot, and you will continue gaining points. You can stop when you have about 60,000 points. At the end of the level, you will gain about eventeen
lives.

Pirate Hat

On level 1-1 destroy Hairy Nanny Daycare right after the miniboss.

Private Eye hat

Beat level 3-2 on Hard.

Soviet Hat

Get to level 2-1.

Tom Fulp hair

Name your hominid tomfulp.