Featured: Top of Home Page/Games/Moving Pixels In Motion: On the Emptiness of Progress By PopMatters Staff / 9 February 2016 Nils Pihl calls it, "Newtonian engagement", that is, when "an engaged player will remain engaged until acted upon by an outside force". That's "progress".
Featured: Top of Home Page/Games/Moving Pixels/Podcasts Moving Pixels Podcast: Our Best Games of 2012 By G. Christopher Williams / 21 January 2013