Gryzor was a port from the Arcade game Contra from Konami. (Also known as Probotector on Nintendo Entertainment system)
The Home Computer's ports (Amstrad CPC port too) were mostly produced by OCEAN company from England.
Gryzor Vs. Contra Vs. Probotector
As said, Gryzor is actually a port from Konami's Contra. Contra was often renamed from countries to countries and system to system for more or less obscure reasons.
Contra was renamed Gryzor because the term Contra could refer to "the Iran-Contra affair" or "Nicaraguan Contra rebels"... which were hot international political topics in 1987.
Nintendo Entertainment System (NES) console version was renamed Probotector in Europe, having the sprites changed from humans to robots due to censorship reasons, political authorities judged it was too violent for European children if the protagonist were humans, and would lead those kids to kill peoples in the street.
Despite those name changes, this is the same game despite in different countries, on different machines and produced by different companies (under license in OCEAN's case).
Gryzor is probably one of the best game available on Amstrad CPC, and is probably featured in every Top10 games for this standard. This is of course not objective but quite accepted amongst the Amstrad community, Gryzor is the symbol of what a well programmed CPC can do.
This is a "Run and Gun" style game, such as games like : Robocop, Midnight resistance... With vertical, horizontal and 3d (sort of) action.
It is well known for :
- Quite Faithfull to the arcade colourful graphics exploiting very well the Mode 0.
- Nice Music.
- excellent playability and fast action.
- varying gameplay
Despite this, this game is not flawless :
- lack of smooth scrolling.
- lack of a proper 2 player mode.
This is probably the best port amongst 8 bit computers, always referenced as such by Amstrad CPC fans in the 8-bit wars.
Unsurprisingly, the MS-DOS PC version was miles behind too.
- Sprites are stored upside down
- Sprites are defined for mode 0 with pen 0 as transparent.