Do graphics matter? Are people only serious about "serious" games? DO communities of players only coalese around big, modern MMOGs?
Obviously, no. But for those who need to be reminded, I give you the 2006 NetHack Tourney (the 2007 tourney is happening right now).
Anyone who’s ever played NetHack can see that it is profoundly re-playable, but if you followed that link, you’d find a thousand specialized ways to play NetHack (play vegan; don’t eat meat, don’t wear leather, don’t attack "animal" monsters). What other game even comes close?!?
Sure, most RPGs and adventure games have some re-playability. Many of them actually encourage you to go back and play all the way through again. Silent Hill 2 lets you play through again with a chainsaw. Resident Evil 4 gives you alternate characters and new weapons when you go back through.
And then there’s Diablo (and Diablo 2), which was intentionally a graphically-updated version of NetHack.
So, IF you build a game with loads of procedurally-generated content and an open answer space, are you garanteed to build a large and loyal player community?