Pygame Example Mass Bullet

import pygame
import random
from pygame.sprite import Group, Sprite

class Entity(Sprite):
    def __init__(self, image, position, anchor="center"):
        super().__init__()
        self.image = image
        self.rect = image.get_rect()
        setattr(self.rect, anchor, position)
        self.center = pygame.Vector2(self.rect.center)

    def move(self, vector):
        self.center += vector
        self.rect.center = self.center

class Bullet(Entity):
    def __init__(self, vector, speed, image, position, anchor="center"):
        super().__init__(image, position, anchor)
        self.vector = vector
        self.speed = speed

    def update(self, delta, area):
        self.move(self.vector * self.speed * delta)
        if not self.rect.colliderect(area):
            self.kill()

class Shooter:
    def __init__(self, position, color, direction):
        self.bullets = Group()
        self.vector = pygame.Vector2(direction) * 8
        self.position = pygame.Vector2(position)
        self.create_bullet(color)
        # Higher number is slower
        self.rate_of_fire = 30
        self.ticks = -1

    def create_bullet(self, color):
        self.image = pygame.Surface((4, 1), pygame.SRCALPHA)
        self.image.fill(color)

    def shoot(self):
        position = self.position + self.vector
        angle = self.vector.as_polar()[1]
        image = pygame.transform.rotate(self.image, -angle)
        bullet = Bullet(self.vector.copy(), 90, image, position)
        self.bullets.add(bullet)
        # Added Second Bullet
        offset = self.vector.rotate(90)
        position += offset
        bullet = Bullet(self.vector.copy(), 90, image, position)
        self.bullets.add(bullet)

    def update(self, delta, ticks):
        if self.ticks == -1:
            self.ticks = ticks
        else:
            while ticks > self.ticks:
                self.shoot()
                self.ticks += self.rate_of_fire
                self.vector.rotate_ip(2)

class Pen:
    def __init__(self, font, color):
        self.font = font
        self.color = color

    def render(self, text):
        return self.font.render(text, 1, self.color)

class Label(Sprite):
    def __init__(self, name, pen, position):
        super().__init__()
        self.pen = pen
        self.name = name
        self.image = pen.render(name)
        self.rect = self.image.get_rect(topleft=position)

    def update_value(self, value):
        self.image = self.pen.render(self.name + " {}".format(value))
        self.rect = self.image.get_rect(topleft = self.rect.topleft)

def main():
    pygame.display.set_caption("Shooters")
    surface = pygame.display.set_mode((800, 600))
    clock = pygame.time.Clock()
    rect = surface.get_rect()
    running = True
    delta = 0
    fps = 60

    shooters = []
    colors = list(pygame.color.THECOLORS.keys())
    direction = pygame.Vector2()
    number_of_shooters = 100
    for i in range(number_of_shooters):
        position = random.randint(50, rect.w - 50), random.randint(50, rect.h - 50)
        direction.from_polar((1, random.randint(0, 360)))
        shooters.append(Shooter(position,
                                random.choice(colors),
                                direction.copy()))

    lab_interval = 100
    lab_ticks = 0
    pen = Pen(pygame.font.Font(None, 30), 'lightblue')
    lab_count = Label("Bullet Count", pen, (10, 10))
    lab_fps =Label("Fps", pen, (rect.centerx, 10))
    labels = Group(lab_count, lab_fps)

    while running:
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                running = False

        surface.fill('black')
        for shooter in shooters:
            shooter.bullets.draw(surface)
            shooter.bullets.update(delta, rect)

        labels.draw(surface)

        ticks = pygame.time.get_ticks()
        for shooter in shooters:
            shooter.update(delta, ticks)

        if ticks > lab_ticks:
            lab_ticks = ticks + lab_interval
            count = sum([len(s.bullets) for s in shooters])
            lab_count.update_value(count)
            lab_fps.update_value(int(clock.get_fps()))

        pygame.display.flip()
        delta = clock.tick(fps) * 0.001

pygame.init()
main()
pygame.quit()