Was reading this article "the problem of engine-building games" and thinking a lot about playable engine-builders. I made a few prototypes of something out of cards but it wasn't very good. The idea started from "what if everyone was building the engine together?", because then no player would be left behind in terms of that exponential growth curve, but to make it a game, there still had to be some element of competition.
And then, of course, I realized I'd messed up because I was making a game rather than a playable so I scrapped it shortly after toying around with it. If I'm going to gamify I can't start with it - I want to make an interesting system, an interesting playable, that can stand on its own first.
So with some more thinking I realized that engine-building games made into playables are, kinda, just incremental games? which is terrible, because i can't stand incremental games. I guess it's not quite an apt comparison because incremental games are engine-building playables given a looping progression.
Anyway, I'm still thinking about how to make a playable out of an engine-building game.