This game uses Overscan in Mode 0. The video RAM is located in the RAM blocks &0000-&3FFF and &C000-&FFFF. Software Crossfire technology brings both screens together. One screen RAM is to be seen on the upper half of the screen, the other screen RAM is shown on the lower half of the screen. Therefore it was necessary to use the interrupt mode 2 of the Z80. The resoluton in Mode 0 is 208(x) * 288(y) using 16 colors. Beside the Overscan there is another hardware effect. Smooth hardware scrolling is used. You scroll through one screen horizontally in about one second.
A special 2D / 3D engine is used for the Return of the Sisters. In this case it works in 2D mode. In the case of [[Gerelakos|Gerelakos]] it works in 3D mode. Since the game engine uses software Crossfire technology and two 16 KB screen RAMs, the interrupt Mode 2 and some other special features this game is being developped for [[FutureOS|FutureOS]]. No other CPC OS provides the needed features.
== Sinners<br> ==