While some Spanish companies reduced the screen in order to get the game better running in low-spec 464, the infamous speccy ports just ran a reduced screen so the ZX Spectrum's code and graphics could run almost "unchanged".
==Real-Time Conversion of Spectrum graphics==
A common way to get the Speccy game running on the CPC was to perform real-time conversion of Spectrum graphics.
* Graphics are stored on the Amstrad in the same format as on the Spectrum (2 colour, 1BPP)
* Amstrad's mode 1 is used to maintain the same pixel resolution.
* A routine converts the graphics on-demand, while the game is running, into the form that is displayed for the screen.
Needless to say, this enabled the port without the use of additional graphics artists, so it was cheaper.
Disadvantages:
* This process takes a lot more CPU power compared to the Spectrum version, because in addition to drawing and erasing the sprites, the pixel data must also be converted at the same time.
* This resulted in a slower game.
* Amstrad version had less colours (often as little as 2 colours)
Advantages:
* Pixel data took less RAM compared to storing it in Amstrad's mode 1 form.
==Monochromatic playfield and Sprite Masks==