It's funny that this was written in 1989, right after the Japanese pulled the industry out of the 80s Atari crash, where shovelware destroyed consumer confidence in Atari products (I know that is a simplification, but the Nintendo Seal of Approval carried weight). The fact is the 90s was riddled with derivatives, where every cartoon character had a derivative side-scroller of varying quality. The scale of a cartridge…
>just changing animation quality, physics, attack methods, and level design So...basically everything about the game but the genre?
But there is some boundary line on the level of effort where a game becomes its own thing. Fortunately for the industry, the number of parameters that can be "tweaked" grew exponentially with each console generation.