About invisible objects, the problem is that the game does sprite multiplexing to increase the number of bullets and items on the screen.
On emulation, all frames appear correctly and all objects are visible.
On real HW, some digital TV sets do not display odd or even frames, because they implement interlacing removal. The result is that some object does not appear or appear only in horizontal stripes.
In this case try changing the settings of the TV in order to avoid interlacing removal. By trial and error I had some improvement on my Sony TV set.