diff --git a/pyshoot.py b/pyshoot.py
index 0e6e3a8..a7f9ee3 100755
--- a/pyshoot.py
+++ b/pyshoot.py
@@ -179,7 +179,10 @@ class Enemy(Object):
 
 	def aim_player(self):
 		""" compute speed vector to aim at current player position """
-
+	
+	def die(self):
+		""" make the enemy dying """
+		globals.enemies_list.remove(self)
 
 def init_gfx():
 	"""graphics initialisation"""
@@ -281,6 +284,14 @@ def transition_fade_to_white():
 	""" lighten every pixels on screen """
 	pass
 
+def handle_enemies_collisions(collisions):
+	""" take the returned dictionnary from pygame.sprite.groupcollide()"""
+	for bullet, enemies in collisions.iteritems():
+		if enemies != []:
+			for e in enemies:
+				e.die()
+			globals.bullets_list.remove(bullet)
+
 ##
 # Main
 ##
@@ -297,7 +308,7 @@ player = Player(['player1_1.bmp', 'player1_2.bmp'], (50, 50), (0, 0))
 globals.player = player
 
 # background
-globals.background = pygame.image.load(os.path.join('data', 'background.bmp')).convert()
+globals.background = pygame.image.load(os.path.join('data', 'background1.bmp')).convert()
 background_rect = globals.background.get_rect()
 globals.screen.blit(globals.background, background_rect)
 pygame.display.flip()
@@ -314,6 +325,11 @@ while not globals.die:
 	globals.moving_objects.update()
 	globals.bullets_list.update()
 	globals.enemies_list.update()
+
+	# collisions
+	ret = pygame.sprite.groupcollide(globals.bullets_list, globals.enemies_list, False, False)
+	handle_enemies_collisions(ret)
+
 	
 	# add player (if it's not already in the group). ugly, but ok for now.
 	globals.moving_objects.add(player)