I see that you are using Bill Porter's library for the PS2 controller.
I googled Bill Porter and found a page with his library.
I downloaded it.
It includes a PS2X_Example sketch that shows how to read many buttons from the controller object.
And then it prints the status of those buttons to the serial monitor.
You likely have this sketch in the directory where your library is.
I dropped the library on my desktop just so I could look at it so the path looks like this for me
C:\Users\vherm\Desktop\madsci1016-Arduino-PS2X-5d2be70\PS2X_lib\Examples\PS2X_Example
See if you can find this example, load it on your board and run it.
Does it show results when you push the other buttons?
Can you find the relevant lines of code that read those buttons?
Let us know how far you get with this or if you run into problems.