Many (if not all) of those games can actually run faster just by getting rid of this CPU-wasting rasters..!
Providing a game had to deal with 1bpp to 2 bpp convertion, Software Sprites and Scrollings... and complicated gameplay... adding some Raster interrupt to the equation is a real dickmove and a good way to waster further more CPU time.
===Partial code re-use for proper CPC games===