diff --git a/.DS_Store b/.DS_Store
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index 0000000..48f3106
Binary files /dev/null and b/.DS_Store differ
diff --git a/alien_invasion.py b/alien_invasion.py
new file mode 100644
index 0000000..d658390
--- /dev/null
+++ b/alien_invasion.py
@@ -0,0 +1,88 @@
+import sys
+import pygame
+from settings import Settings
+from ship import Ship
+from bullet import Bullet
+from pygame.sprite import Group
+
+
+class AlienInvasion:
+  """Overall class to manage game assets and behavior."""
+
+  def __init__(self):
+    pygame.init()
+    self.clock = pygame.time.Clock()
+    self.settings = Settings()
+    self.screen = pygame.display.set_mode((0,0), pygame.FULLSCREEN)
+    self.settings.screen_width = self.screen.get_rect().width
+    self.settings.screen_height = self.screen.get_rect().height
+    pygame.display.set_caption("Alien Invasion")
+    self.bg_color = self.settings.bg_color
+    self.ship = Ship(self)
+    self.bullets = Group()
+
+  def run_game(self):
+    """Start the main loop for the game."""
+    while True:
+      # Check for events and update the game state.
+      self._check_events()
+      self.ship.update()
+      self._update_bullets()
+      # Redraw the screen during each pass through the loop.
+      self._update_screen()
+      self.clock.tick(60)
+
+  def _check_events(self):
+    """Respond to keypresses and mouse events."""
+    for event in pygame.event.get():
+      if event.type == pygame.QUIT:
+        sys.exit()
+      elif event.type == pygame.KEYDOWN:
+        self._check_keydown_events(event)
+      elif event.type == pygame.KEYUP:
+        self._check_keyup_events(event)
+
+  def _check_keydown_events(self, event):
+    """Respond to key presses."""
+    if event.key == pygame.K_RIGHT:
+      self.ship.moving_right = True
+    elif event.key == pygame.K_LEFT:
+      self.ship.moving_left = True
+    elif event.key == pygame.K_q:
+      sys.exit()
+    elif event.key == pygame.K_SPACE:
+      self._fire_bullet()
+
+  def _check_keyup_events(self, event):
+    """Respond to key releases."""
+    if event.key == pygame.K_RIGHT:
+      self.ship.moving_right = False
+    elif event.key == pygame.K_LEFT:
+      self.ship.moving_left = False
+
+  def _fire_bullet(self):
+    """Fire a bullet if the limit is not reached."""
+    if len(self.bullets) < self.settings.bullets_allowed:
+      # Create a new bullet and add it to the bullets group.
+      new_bullet = Bullet(self)
+      self.bullets.add(new_bullet)
+
+  def _update_bullets(self):
+    """Update position of bullets and remove old bullets."""
+    self.bullets.update()
+    for bullet in self.bullets.copy():
+      if bullet.rect.bottom <= 0:
+        self.bullets.remove(bullet)
+
+  def _update_screen(self):
+    """Update images on the screen and flip to the new screen."""
+    self.screen.fill(self.bg_color)
+    for bullet in self.bullets.sprites():
+      bullet.draw_bullet()
+    self.ship.blitme()
+    pygame.display.flip()
+
+if __name__ == '__main__':
+  # Make a game instance and run the game.
+  ai = AlienInvasion()
+  ai.run_game()
diff --git a/bullet.py b/bullet.py
new file mode 100644
index 0000000..cb0c09a
--- /dev/null
+++ b/bullet.py
@@ -0,0 +1,24 @@
+import pygame
+from pygame.sprite import Sprite
+
+class Bullet(Sprite):
+  """A class to manage bullets fired from the ship."""
+
+  def __init__(self, ai_game):
+    """Create a bullet object at the ship's current position."""
+    super().__init__()
+    self.screen = ai_game.screen
+    self.settings = ai_game.settings
+    self.color = self.settings.bullet_color
+    self.rect = pygame.Rect(0, 0, self.settings.bullet_width, self.settings.bullet_height)
+    self.rect.midtop = ai_game.ship.rect.midtop
+    self.y = float(self.rect.y)
+
+  def update(self):
+    """Move the bullet up the screen."""
+    self.y -= self.settings.bullet_speed
+    self.rect.y = self.y
+
+  def draw_bullet(self):
+    """Draw the bullet to the screen."""
+    pygame.draw.rect(self.screen, self.color, self.rect)
diff --git a/images/ship.bmp b/images/ship.bmp
new file mode 100644
index 0000000..9a94402
Binary files /dev/null and b/images/ship.bmp differ
diff --git a/settings.py b/settings.py
new file mode 100644
index 0000000..c066102
--- /dev/null
+++ b/settings.py
@@ -0,0 +1,23 @@
+class Settings:
+  """A class to store all settings for Alien Invasion."""
+
+  def __init__(self):
+    """Initialize the game's static settings."""
+    self.screen_width = 1200
+    self.screen_height = 800
+    self.bg_color = (230, 230, 230)
+
+    # Ship settings
+    self.ship_speed = 1.5
+
+    # Bullet settings
+    self.bullet_speed = 3.0
+    self.bullet_width = 3
+    self.bullet_height = 15
+    self.bullet_color = (60, 60, 60)
+    self.bullets_allowed = 3
+
+    # Alien settings
+    self.alien_speed = 1.0
+    self.fleet_drop_speed = 10
+    self.fleet_direction = 1  # 1 represents right; -1 represents left
diff --git a/ship.py b/ship.py
new file mode 100644
index 0000000..6a90b47
--- /dev/null
+++ b/ship.py
@@ -0,0 +1,28 @@
+import pygame
+
+class Ship:
+  """A class to manage the ship."""
+
+  def __init__(self, ai_game):
+    """Initialize the ship and set its starting position."""
+    self.screen = ai_game.screen
+    self.settings = ai_game.settings
+    self.image = pygame.image.load('images/ship.bmp')
+    self.rect = self.image.get_rect()
+    self.rect.midbottom = self.screen.get_rect().midbottom
+    self.x = float(self.rect.x)
+    self.moving_right = False
+    self.moving_left = False
+
+  def update(self):
+    """Update the ship's position."""
+    # Update the ship's x value, not the rect.
+    if self.moving_right and self.rect.right < self.screen.get_rect().right:
+      self.x += self.settings.ship_speed
+    if self.moving_left and self.rect.left > 0:
+      self.x -= self.settings.ship_speed
+    self.rect.x = self.x
+
+  def blitme(self):
+    """Draw the ship at its current location."""
+    self.screen.blit(self.image, self.rect)