What is happening right now?

drewr1122 provided one of the two methods. It was your task to create the other one (setScore). However, methods like setScore and getScore are truly only helpful for access to the score from other classes. The WhiteCell class already has access to the score because it is defined in its class -- so those methods are not needed at all (at least for use in the WhiteCell class).

Remove line 9 from the Klingonen class. The Greenfoot class delay method will pause everything, not just spawning of actors. Use an int field in your subclass of World to count act cycles and presume 60 acts to equal one second of time. When the counter reaches 600 (60 acts times 10 secconds) spawn a Klingonen object and reset the counter to zero (use an act method in your extension of World.

I am not sure what you mean by "image below is resting". If you want clarification on some point, you will have to be more specific, show all codes used for scrolling (other than the Scroller class itself (which should not be modified) and provide sizes of both your world and the scrolling background image.

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