@AnJoMorto, are you not creating them with a true boolean? addObject(new Enemy(), x, y, true);

@Roshan123, adding of collection png not currently working properly. Been that way for some time now. Note my latest collection had issues as well.

Field declaration: GreenfootSound background_music; In constructor: if (background_music == null) { background_music = new GreenfootSound("Background_music.mp3"); }

@SwaggyXiao, please refer to my Scrolling Tutorial scenario on image scrolling (see main text and link at bottom on "Actor follow scrolling code"). The scenario is located at: https://www.greenfoot.org/scenarios/18226

Scaling and re-scaling an image will usually distort and eventually "destroy" an image. Better would be to copy the image and scale it once; then go back and forth setting the appropriate image.

The background image must remain completely opaque. Using "clear()" on it makes it completely transparent, which is why you are getting trails and added residual images.

@Roshan123, iZip should be able to unzip them; although, I have no personal experience with iZip. You might need to re-suffix the file from ".gfar" to ".zip" for it to work -- possibly not.