Hello,
Here is the practice script I developed for my other project. Feel free to use and/or adapt it for your uses. I may add some documentation in the future depending on my schedule. It is very rudimentary at the moment as you can only have 1 instance of the same sprite on the screen at time, but it is still very functional in it's current state.
At the moment the sprite controls the X axis scrolling based on the positive and negative of that axis. For example, hitting the left arrow moves the scrolling to the negative and right moves to the positive of the axis. Thus the player can scroll forward and backwards. Objects occur based on their place in a table loaded with each sprite. The most notable omission I can think of is there is no enemies and thus examples of how their movement would be adjust based on the changing x axis.
If you want to view it:
http://scratch.mit.edu/projects/mikebmac/3241697
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Added an example mob that show a possible way to move a mob with the scrolling screen.
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