Atari Game Tools: Atari STE game engine - Combined H+V Scroll
This is a modified version of the main SHMUP demo/example #1 (see other video) using the AGT engine on Atari STE. It combines vertical scrolling with horizontal.
While it does look less pretty (caused by the inappropriate palette being forced in there with the changed background) and some game elements need updated, the idea here was to just show how easily an existing game can be modified to use a different scrolling design with only a few lines of code changed...
Once again, YT can't quite handle the field interlacing effect, and this causes some strange gfx artifacts. Close enough though.
Alternate background from Thunder Cross (arcade)