Hello everyone. 
Anyone can help me? I have problem here… 
Hope anyone can help me…
Hard to fix from images only, maybe with some event-screenshots we can do more to help you
If you change the project size, you have to scale all your objects too, because you are modifying how much of the scene you can see.
Maybe you want to modify the window size through event actions, it shows your camera view in the window area, scaling the objects automatically.
The enemies seems rotated, do you modify the angle of the enemy object in your events?
Obviously they are created in the tower position, check the event where you create or modify the enemies position.
About the bullet direction, if you are flipping the sprite, the bullet won’t know it, you must add the conditions: if tower is not flipped shoot with angle = 0, if tower is flipped shoot with angle = 180.
Finally to create the enemies at left (0) or right (640) you can create a temporary variable pos = Random(1), it will be 0 or 1.
Then if pos = 0: Create the object at left (0), or better with some margin (e.g. -50) if the origin point of the enemy sprite is at 0;0
If pos = 1: Create the object at right (640)
