[crq-yml]

I'm pretty sure that it's not exactly about the code, it's a case of having honed skills and techniques from multiple different sources - John Romero was bouncing around the industry and working on both larger and smaller productions, multiplatform ports, and different approaches to engine/content(he got his hands on both Origin's and Infocom's stuff, as well as a few other places) - the number of references he brought to the table could not be underestimated. John Carmack didn't have that same experience but would have been able to take a description from Romero of "at Origin we did it like this" and aim to make a very efficient version of it - his growth into borrowing academic research for inspiration came a little later. And there was also the early influence of Tom Hall who was older, able to communicate what he wanted as a producer and probably steered the programming team away from wrong turns a few times.

When you have the experience, you already know how long it takes to implement the majority of the game, when we're speaking of these early 2D games using bitmaps, tiles, small animations and some monospace text. The gameplay code is game-jam sized in most instances, so a majority of it was I/O code and asset pipelines. You can chart a safe course to get through one tiny project, and then another, and another, and build a best-of the routines that worked. The coding style would be assembly-like at this time even if they were using C - no deep callstacks, mostly imperative "load and store", which allows for a lower level form of reuse than is typical these days by breaking down the larger algorithm into "load", "mutate", "mutate", "mutate", "store" each as separate routines. So you end up with some tight code when you get to run it through a lot of projects. Softdisk provided the opportunity for building that and getting paid.