If the screen of the game is small you'd probably get away with using active objects and just wrapping them when they leave the frame. Im pretty sure the active system box thingy can achieve a scrolling effect...or not.
I tried doing something like this before in the vein of NES Commando or Tiger Heli before with one big active that continuously added +1 to its Y value every (0.X) amount of seconds. The only thing there is that is stopped when it got to the end because that's where the big boss was supposed to be. It had a lot of slowdown to it too, but that was on my old computer which slows everything down anyway.
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