My greatest published achievements technically would have to be fitting BBC Cassette "Elite" into 32K of RAM including the screen, and later the Nintendo Entertainment System conversion of "Elite" that used a character mapped display and a single NES controller. The NES is my favourite published conversion and was not thought technically feasible until we'd done it.
I interpret this as meaning his favourite version is the BBC Micro cassette version, while his favourite conversion is the NES one. But I'm a BBC fanboy, so that might just be me being hopeful. :-)
The CHR ROM on NES Elite was actually RAM... allowing for something akin to "bitmap mode" on the TI-99/4A or C64 where they can use the CHR memory as a framebuffer in which to draw those vector graphics.
Indeed - "slaves" got changed to "robot slaves", while "narcotics" became "rare species" and "liquor/wines" became "beverages". You can still trade firearms, though, so its not entirely squeaky clean...
Nintendo would have had a hell of a time censoring firearms from videogames. Nudity, slavery, narcotics, and alcohol are easy; violence and firearms form the basis of many/most popular video games.
Probotector is Contra @50Hz with all humans replaced by robots, but still lots of firearms and violence.
Yeah, that's my guess. Violence towards humans in video games was often prohibited in Germany, so drop it for the whole region, because two releases is hard.
(He liked the 32-bit Archimedes port the best overall.)