You have to click the button. It increases your CPS (Clicks per second)
You get random upgrades per random range of time - around 10-20 seconds.
In a normal and hard difficulty, first upgrade always starts at 20th second
In insane, it starts at 10th second with smaller range of time.
Your goal is to survive until 10 game minutes (paused time not included)
Insane difficulty differs - it requires 4 game minutes.
Each 500 real clicks (first one exclusively is at 100), you get an upgrade that adds up to your total clicks per each click.
later this page will be filled with more info