Alien Hominid

There are two ways to unlock a hat:
a) perform a task (e.g. blow up a certain building, finish a certain level)
b) use a special name as your name
In most cases, you will hear an air horn sound when you unlock something (I've
noticed that for stage-beating tasks, for some hats the horn does not sound).

Here is a list of all hats in menu order and the tasks that unlock them:

Get to level 3-1.

Beat the final boss on Hard mode.

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

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

In the Player Name Option Screen, name your Hominid the following to get the new head topping for two-player games:

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

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.