Good video, Jim.
Whether you have the loosest of rules or win/loss states like Dear Esther, or stricter rule sets like the console games we typically classify as games, I think the common thread between them is that we have the ability to play in them.
You might be more inclined (or maybe not!) to actually play around with/explore your world and actions in a game with loose rules, like Dear Esther (I'd argue that this is the appeal of sandbox games). With other games (JRPG's, MMOG's, fighters to an extent, most story based games, etc), you might be less inclined to play/explore the game and its mechanics, or rather/instead are more motivated to complete the outlined task to progress events or a story. Arguably, there's still room to 'play' there.
So, is this argument over now?[footnote]Also, is that a TV that looks like an apple???[/footnote]