As an expert Python developer, reflect on the following code and its output. Identify any issues or potential improvements. Then, provide an improved version of the code.

Original Code:
<code class="python">
([['
You are an expert Python developer. Based on the following task description, generate clean, well-documented, and functional code.

Task Description:
write a snake game

Instructions:
- Provide only the necessary code without additional explanations.
- Enclose the code within <code class="python"> tags.
- Ensure the code follows best practices and coding standards.
- Include comments where necessary for clarity.
', '
import pygame
import sys
import random

# Initialize Pygame
pygame.init()

# Constants
SCREEN_WIDTH = 640
SCREEN_HEIGHT = 480
CELL_SIZE = 20

# Colors
WHITE = (255, 255, 255)
LIGHT_GREEN = (160, 255, 160)
GREEN = (0, 255, 0)
DARK_GREEN = (0, 100, 0)
RED = (255, 0, 0)
BLACK = (0, 0, 0)

# Directions
UP = \'up\'
DOWN = \'down\'
LEFT = \'left\'
RIGHT = \'right\'

def draw_grid(surface):
    """Draws grid lines on the surface."""
    for x in range(0, SCREEN_WIDTH, CELL_SIZE):
        pygame.draw.line(surface, LIGHT_GREEN, (x, 0), (x, SCREEN_HEIGHT))
    for y in range(0, SCREEN_HEIGHT, CELL_SIZE):
        pygame.draw.line(surface, LIGHT_GREEN, (0, y), (SCREEN_WIDTH, y))

def random_position():
    """Generates a random position within the grid."""
    x = random.randint(0, (SCREEN_WIDTH - CELL_SIZE) // CELL_SIZE) * CELL_SIZE
    y = random.randint(0, (SCREEN_HEIGHT - CELL_SIZE) // CELL_SIZE) * CELL_SIZE
    return x, y

def game_over(surface, score):
    """Displays the game over screen."""
    font = pygame.font.Font(None, 72)
    game_over_text = font.render(\'Game Over\', True, RED)
    score_text = font.render(f\'Score: {score}\', True, WHITE)

    surface.blit(game_over_text, (
        SCREEN_WIDTH / 2 - game_over_text.get_width() / 2,
        SCREEN_HEIGHT / 3
    ))
    surface.blit(score_text, (
        SCREEN_WIDTH / 2 - score_text.get_width() / 2,
        SCREEN_HEIGHT / 2
    ))

    pygame.display.update()
    pygame.time.wait(3000)

def main():
    screen = pygame.display.set_mode((SCREEN_WIDTH, SCREEN_HEIGHT))
    pygame.display.set_caption(\'Snake Game\')
    clock = pygame.time.Clock()
    font = pygame.font.Font(None, 36)

    # Initial snake and food position
    snake_pos = [(SCREEN_WIDTH // 2, SCREEN_HEIGHT // 2)]
    direction = RIGHT
    change_to = direction

    food_pos = random_position()
    score = 0

    while True:
        # Event handling
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                pygame.quit()
                sys.exit()
            # Controls
            elif event.type == pygame.KEYDOWN:
                if event.key == pygame.K_UP and direction != DOWN:
                    change_to = UP
                elif event.key == pygame.K_DOWN and direction != UP:
                    change_to = DOWN
                elif event.key == pygame.K_LEFT and direction != RIGHT:
                    change_to = LEFT
                elif event.key == pygame.K_RIGHT and direction != LEFT:
                    change_to = RIGHT

        direction = change_to

        # Update snake position
        head_x, head_y = snake_pos[0]
        if direction == UP:
            head_y -= CELL_SIZE
        elif direction == DOWN:
            head_y += CELL_SIZE
        elif direction == LEFT:
            head_x -= CELL_SIZE
        elif direction == RIGHT:
            head_x += CELL_SIZE
        new_head = (head_x, head_y)

        # Collision with boundaries
        if (head_x < 0 or head_x >= SCREEN_WIDTH or
            head_y < 0 or head_y >= SCREEN_HEIGHT):
            game_over(screen, score)
            pygame.quit()
            sys.exit()

        # Collision with self
        if new_head in snake_pos:
            game_over(screen, score)
            pygame.quit()
            sys.exit()

        snake_pos.insert(0, new_head)

        # Snake eats food
        if new_head == food_pos:
            score += 1
            food_pos = random_position()
        else:
            snake_pos.pop()

        # Drawing
        screen.fill(BLACK)
        draw_grid(screen)

        # Draw snake
        for pos in snake_pos:
            pygame.draw.rect(
                screen, GREEN,
                pygame.Rect(pos[0], pos[1], CELL_SIZE, CELL_SIZE)
            )

        # Draw food
        pygame.draw.rect(
            screen, RED,
            pygame.Rect(food_pos[0], food_pos[1], CELL_SIZE, CELL_SIZE)
        )

        # Display score
        score_text = font.render(f"Score: {score}", True, WHITE)
        screen.blit(score_text, [10, 10])

        pygame.display.update()
        clock.tick(10)

if __name__ == "__main__":
    main()
</code>']], 1, '', {'interactive': True, '__type__': 'update'})
</code>

Execution Output:
❌ Execution Error:
  File "C:\Users\Shadow\AppData\Local\Temp\tmp6qt1s_ub.py", line 1
    ([['
       ^
SyntaxError: unterminated string literal (detected at line 1)


Instructions:
- Analyze the code and its output.
- Identify any errors, inefficiencies, or areas for improvement.
- Provide an improved version of the code within <code class="python"> tags.
- Include a brief explanation of the changes made.
- Ensure the code does not contain HTML tags or entities.