Where can I find the 3 hidden peaches ? , last one to open the special "reward"
Two of the peaches are in the preferences menu, one in the settings tab (the cogwheel tab), and one in the information tab (the "i" tab on the right side of the screen).
The other one is in the "hamburger menu" (the three lines menu) on the top right of he screen when you are in the game, it's at the bottom of the screen and is tricky to click on because the menu like to close if your mouse moves too far from the right side of the screen.
I struggled with that too. Hope this helps.