Click the pizza to gain score (click and HOLD to get score the fast way), click the "upgrades" button to go to the place where you buy upgrades. Upgrades cost NEGATIVE amounts of score.
Tutorial for the nice graphics is from @griffpatch. Cooker: +1 CPS (clicks per... 1/5 OF A SECOND) Chef: +3 CPS Baker: +9 CPS Scientist: +1 CPS per second
