I've actually been really impressed by Shenzhen I/O (http://www.zachtronics.com/shenzhen-io/ http://www.zachtronics.com/shenzhen-io/), which is a game where you

I've actually been really impressed by Shenzhen I/O (http://www.zachtronics.com/shenzhen-io/ http://www.zachtronics.com/shenzhen-io/), which is a game where you have to program microcontrollers to build weird products. The built-in programming language is an ultra-simple assembly language, with either one or two registers, and about a dozen operations. Program length is limited to about 10 or 15 statements. There are external ROM and RAM modules which store about 20 values. Every challenge comes with a pre-made test suite. Something about these extreme restrictions and the simplicity make for excellent, puzzle-style gameplay. And I think you could add a Shenzhen I/O-like "microcontroller" to a lot of automation games (like Factorio: https://www.factorio.com/ https://www.factorio.com/) and it would work very well. I think that one of the problems with adding traditional programming languages to games is that there are no constraints to make it challenging, and that you can write fairly large programs. But a deliberately limited and simple language could be fun.