Gryzor was a port from the Arcade game Contra from Konami. (Also known as Probotector on Nintendo Entertainment system)
The home computer ports (Amstrad CPC port included) were mostly produced under licence by OCEAN, the company from England famous amongst Amstrad CPC user for it's good ports.
Gryzor Vs. Contra Vs. Probotector
As said, Gryzor is actually a port from Konami's Contra. Contra was often renamed from country to country 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 people in the street.
Despite those name changes, this is the same game regardless of country or machine or being produced by different companies.
Gryzor is also one of the best game available on Amstrad CPC and is probably featured in every Top 10 games for this system. This is of course not objective but 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 in the same vein as: Robocop, Midnight resistance... With vertical, horizontal and 3d (sort of) action.
It is well known for :
- Being quite faithful to the arcade's colourful graphics. It exploits CPC's mode 0 very well.
- excellent playability and fast action.
- varying gameplay
Despite this, this game is not flawless :
- lack of smooth scrolling.
- lack of an entire stage.
- lack of certain bosses/mini-bosses
In CPC owner's view it is probably the best port amongst 8 bit computers and stands up well against the other 8-bits in a fair comparison. It is always referenced as such by Amstrad CPC fans in the 8-bit wars.
Even the C64 and MSX ports, two machines often judged superior to Amstrad CPC in many ways, were somewhat inferior compared to the CPC version. Unsurprisingly the MS-DOS PC version was miles behind too.
- Sprites are stored upside down (bottom to top)
- Sprites are defined for mode 0 with pen 0 as transparent
- An animation is composed of frames. Each frame is defined like Renegade, where there are one or more sprites with x,y offset and width, height.
- The tile map is composed of macro tiles.
- Macro tiles are 4 tiles wide.
- Each tile is 4x8 mode 0 pixels stored left-to-right and top-to-bottom.
- Supports 128 KB of RAM (to load the whole game at once)
- Each level's data appears to define the animations, map and sprites.
- Sprites are stored with pixels from left-to-right like normal.
- Unlike Renegade, the sprite draw list can have multiple entries for a character. For example the run and shooting animation, is two separate items in the list, each with it's own animation. The legs and the body having different animations allowing the leg animation to be re-used with multiple body animations.
- Level tiles appear to be shared across all levels
- Macro tiles are either 8 or 7 tiles tall.
- Level tiles are shared across levels.
- The encoding of the map is different.
- Unlike Renegade the sprites do not appear to be sorted in Y - at least not for level 0.
- The animation data has an additional byte before the number of frames. This appears to be used for temporary data.
- Character y origin appears to be at waist position.
Level 2, where the action is inside, the left half of the screen is drawn and then the graphics for the corridor are mirrored to draw the right half.