Thats a great article and truly a great insight to different parts of game dev in general. I always get astonished by this kind of stuff. Most games today are really either over simplistic to the extend of linearity or too complicated to be approachable by the casual gamer. But this thing has a nice simple gameplay and at the same time it has a lot of complexity and possibilities, and I really like that!
There should be some kind of source that would concentrate on games with complex behavioral model and intriguing game mechanics and yet simplistic gameplay. I might try to write an article about this things in general if I find some time, maybe motivating some game programming prodigies out there
I have read the article the day you posted, just forgot to reply