These Amstrads were the successors of the Amstrad CPC 6128. Amstrad tried to prolong the life of the old 8-bit Amstrads, which suffered from competition with the new 16-bit home computers (like the Amiga and Atari ST).
Amstrad made some important modifications to maintain the level of its machines, the CPC 6128 Plus became 95% compatible with the CPC 6128 (using the same operating systems AMSDOS and CP/M 3.0). However, some software did not run on the plus range and amstrad official statement was that the programmers where lazy and used bad programming in some software resulting in crashes on this machine.
Several new features were added: hardware scrolling, increased color palette, an enhanced sound chip, a cartridge port, and a redesigned keyboard. Some of these features were not even present (yet) on certain 16-bit computers (Atari STf didn’t have hardware scrolling or sprites). Regardless, this new version of the CPC didn’t last long.
The system offers 16 hardware sprites at a size of 16×16 pixels. The sprites are using 15 other colors than the 16 of the palette, and have x/y zoom. The soundchip is the same AY as on the CPC, but controlable with a DMA.
As Atari did with the 65-XE when it reached the end of its life, so Amstrad made a game console from the Amstrad CPC Plus hardware called the GX 4000. This console used the same programs as the computer but were supplied on cartridges.