Super Xevious

I've been looking at the differences between Xevious and its sequel, Super Xevious. IIUC Super Xevious was purely a ROM upgrade, so no new hardware. In fact, the SOUND CPU ROM is identical, as are the background map ROMs. Both the MAIN and SUB CPU ROMs are different, though at a glance, only superficially so. Super Xevious is obviously built on the same code base.

I've been through the SUB CPU ROM in more detail (it's smaller than MAIN) and I can say there are six (6) new enemies - or more specifically, 6 new object handler functions. Some of them may implement different behaviours (variants) for the same enemy sprite.

I also ran my map tool over the ROMs and produced maps of all the secret objects. Like Xevious, there are 46 Sol Towers and 4 Bonus Flags - mostly in different locations. In case you're not aware, Xevious had 46 Sol Towers defined in the object data table but only 45 were visible during the game; a 'feature' of the implementation actually deletes the 46th Tower before it even scrolls onto the screen.

Why am I looking at it? It would be relatively trivial to add Super Xevious to the Neo Geo (or Amiga). There should in theory be no changes at all to the OSD layer code, only the transcode of the additional/modified code. It may even be possible to build both from the same code base! But it would be a fairly tedious process, and at least several weeks effort. I would likely add a menu to allow the same image to play either one, like some of the Xevious compilations (PSX IIRC?).

I'm not planning on adding it immediately, but the next Beta may at least have provision for high score load/save for both variants.