The Dink Network

Of course NPC dialogue should count if it's presented realistically; It's actually a huge part of what makes epics... well, epic. I understand some conversations in Malachi the Jerk are actually quite long and more spread of NPC dialogue could be a good thing, but it's not anywhere near your example of eight hours of NPC dialogue on a single sprite. Using your same argument I could discount length from mattering at all simply by using the teleporter example mentioned earlier. Since obviously that doesn't make sense, I hope you realize that dialogue does truly matter when it comes to what should and shouldn't be called an epic. Dialogue = gameplay. Sure it's linear and all you are doing is reading or occasionally choosing an option, but you are still actively invested in a game when it's doing dialogue properly.

That said, Malachi is a border case. I don't see anything wrong with calling it either an epic or a quest. Both terms are close enough to fit it accurately in my eyes.

Edit: Checking my data where I did everything I could find, it is very close to the 6 hour mark. I think to simply beat the game it could be done quickly, but then again so can the Dink Smallwood original game. In fact I have a data for the original Dink Smallwood clocking in at only 4 hours with basically everything done that I can minus the firebow. Not a fair comparison though, since I've only played through Malachi one time.