It's their list, they can do what they want. But, for example, I know you play League of Legends, a game completely different then the game that launched four years ago. The Dominion mode could have been 2011 GOTY. Same with MMOs like World of Warcraft and the expansions. If an incomplete game like KRZ can be on the list, then these games could technically be allowed since the the only criteria for a game to included seems to be "we played this part this year".
But this is getting into what a site deems to be worthy. They could have whatever game they wanted on the list: it's their list. But what if the last episodes are horrible? What if they're amazing but now because it won GOTY in 2013 it can't win again? Hell, maybe it can!
Maybe I'm just confusing myself, but having an episode of an incomplete game win is confusing to me.