Yeah STS is a pretty interesting case because it's a game from a Java dev who wanted his own thing. So he programmed it by hand (using libraries like LibGDX, of course). The part that impressed me the most is how he mentions he spent two weeks getting the played cards part working, and it shows; I've played a few "card game" video games and STS' has, by far, the best and most fluid playing. As in, when I click and let go it does exactly as I would expect it to.