Re : Adding wav file

Perhaps because you don't play it? At least, my eyes doesn't see anything like that in the code you show.

Side notes:
- Put size() at the top of setup().
- You will load img2 on each frame after 5 seconds...
Try:

1.   if(millis()<5000)
2.   {
3.   image(img1, 0, 0);
4. }
5. else{
6.   if (img2 == null) {
   
7.     img2 = loadImage("gamescreen.jpg");
8.   }
   
9.   image(img2,0,0);
10.   //rest of code
11. }
12. }

Your code will go faster!