in levels
you have

1.   numBalls = 2;

so shoudl I take it out of levels. dont really understand what you mean

delete it there

I did still no luck

Hello,

I like the idea of the game because you have to see where the eyes look first and then to aim precisely. I like that. 

I made the array now much bigger (3000) and new balls come in it at array-pos "numBallsAtTheMoment" in this array. This number gets increased. Better use arrayList here instead of array later.

You attempted to call setup() again in levels() - that's not a good idea, because
among other things you also call size again.
Also, the program was generating the same first balls in setup() again, starting with new again.
There were no new balls coming in. Instead now in levels() one new ball is added at the end of the array (at array-pos "numBallsAtTheMoment").

I also removed delay - it looks bad when all Balls stop suddenly. It is not recommended anyway. Use a timer instead.

Consider renaming the function "levels" - it is mouseChecking or so not levels.

Also the function ball() directly after drawing is redundant to your class.
Why not use the class and consider the ball at pos 0 in the array as your special ball
that the eyes are following?

1. float bx = random (500);  // redundant
   
2. float by = random (500);  // redundant
3. float ballSpeedX = random (2.0, 4.0);  // redundant
4. float ballSpeedY = random (2.0, 4.0);  // redundant
5. 
   
6. final int numBallsAtTheBeginning = 3; // how many you have at the beginning
   
7. final int numBallsInTotal = 3000;  // how many you can have in total till program crashes
   
8. int numBallsAtTheMoment = 0;  // how many you have now
9. 
   
10. Ball[] balls = new Ball[numBallsInTotal];
11. 
    
12. void setup ()
13. {
14.   size (500, 500);
15.   for (int i = 0; i < numBallsAtTheBeginning; i++) {
16.     balls[i] = new Ball(random(width), random(height), 20, i, balls, random (2.0, 4.0), random (2.0, 4.0));
17.   }
18.   numBallsAtTheMoment=numBallsAtTheBeginning;
19. }
20. void draw ()
21. {
22.   smooth ();
23.   background (0);
24.   face ();
25.   for (int i = 0; i<numBallsAtTheMoment; i++) {
26.     balls[i].move();
27.     balls[i].display();
28.     println (i);
29.   }
30.   ball ();
31.   levels ();
32. }
33. // ------------------------------------------------------------
34. 
    
35. void ball ()   // redundant
36. {
37.   bx += ballSpeedX;
38.   by += ballSpeedY;
39.   if (bx>width || bx<0) {
40.     ballSpeedX = ballSpeedX * -1;
41.   }
42.   if (by>height || by<0) {
43.     ballSpeedY = ballSpeedY * -1;
44.   }
45.   fill (color(#C61C1C));
46.   ellipseMode (CENTER);
47.   ellipse (bx, by, 20, 20);
48. }
49. void levels () // checkMouseForMakingNewBall
    
50. {
51.   if (mousePressed == true &&
52.     mouseX > bx-10 && mouseX < bx+10 &&
53.     mouseY > by-10 && mouseY < by+10)
54.   {
55.     // delay (1000);
56.     balls[numBallsAtTheMoment] = new Ball(random(width), random(height), 20, numBallsAtTheMoment, balls, random (2.0, 4.0), random (2.0, 4.0));
57.     numBallsAtTheMoment++;
58.   }
59. }
60. void face ()
61. {
62.   ellipseMode (CENTER);
63.   fill (color(#D6AFD1));
64.   ellipse (250-30, 250, 42, 42);
65.   ellipse (250+30, 250, 42, 42);
66.   fill (color(#FC08E0));
67.   ellipse ((bx/20)+206, (by/20)+238, 10, 10);
68.   ellipse ((bx/20)+266, (by/20)+238, 10, 10);
69. }
70. // ---------------------------------------------------
71. class Ball {
72.   float x, y;
73.   float diameter;
74.   float vx;
75.   float vy;
76.   int id;
77.   Ball [] others;
78.   Ball(float xin, float yin, float din, int idin, Ball[] oin, float vxin, float vyin) {
79.     x = xin;
80.     y = yin;
81.     diameter = din;
82.     id = idin;
83.     others = oin;
84.     vx = vxin;
85.     vy = vyin;
86.   }
87.   void move() {
88.     x += vx;
89.     y += vy;
90.     if (x + diameter/2 > width) {
91.       vx = vx*-1;
92.     }
93.     else if (x - diameter/2 < 0) {
94.       x = diameter/2;
95.       vx = vx*-1;
96.     }
97.     if (y + diameter/2 > height) {
98.       y = height - diameter/2;
99.       vy = vy*-1;
100.     }
101.     else if (y - diameter/2 < 0) {
102.       y = diameter/2;
103.       vy = vy*-1;
104.     }
105.   }
106.   void display() {
107.     fill(color(#C61C1C));
108.     ellipse(x, y, diameter, diameter);
109.   }
110. }

Greetings, Chrisir