I'm not sure having only a basic ability to shift the screen around would have been much use without additional hardware support. Such as sprites for example. Having to render lots of software sprites over nothing more than a shiftable 24k lump of RAM would get very messy code wise. Especially with the need for double-buffering to avoid glitching/flicker, Etc.
Not to mention the poor old Z80 would still have a shedload of work to do shunting the required data around. Any scrolling game running at less than 50-fps with only half-a-dozen or so on-screen entities really wouldn't be worth the effort! Fast shoot-em-ups are awful at anything less than TV frame-rates. Even slow Z80-based systems such as the Master System managed to do full-colour, full-screen 50-fps scrolling with full-colour sprites (albeit in limited numbers) over the top. But then it did have a tile-based system for the background which, although (for the most part) it is more limiting than a true bitmap, it did mean the Z80 had very little work to do to maintain a nice scrolling backdrop. Besides, there's something *pure* about having a chunk of RAM and a CPU - and not much else! Chris.
