Added requirements.txt

Fixed projectilespawn from enemys

levels.py

@@ -10,6 +10,9 @@ class level(object):
         self.num_enemys = num_enemys
         self.spawn_waves = spawn_waves
         self._completed = False
+
+        def run(self):
+            pass
         
 class first_level(level):
     def __init__(self, name, size: tuple, num_enemys, spawn_waves) -> None: