My point was the OSR style game doesn't use DCs the way a modern game does and the GM does a lot more... GMing.You just need a set of rules for determining DCs. That's easy to code.
The only thing that's challenging for a computer is creating engaging story and characters (and even that might be close). You don't need that for an OSR game, that's the players' job, insofar as it happens at all.