Looking at the successful indie games, Minecraft first and foremost, the key simply seems to be to make something people have never seen before, and do it well. Notch made Minecraft as leanly as possible - by himself. He didn't hire anyone until he already had significant revenue. Now, before it's even out of beta, he's made 30MM in revenue.
Gaming is not a new field, and I think that it's a mistake to apply web startup ideals to an industry with many well-established success stories over 3 decades. All successful development houses got their start the same way - they made a great game that people loved, then another. When Gabe Newell started Valve, he looked at the Quake II's of the world, and said, "this is stupid. The last game had a double-barrel shotgun, so you put 4 barrels on this one and call it an improvement?" They made a great game by focussing on gameplay and the players' experience.
The key seems to be that while the major publishers focus on graphics and production value, the upstarts focus on gameplay. EA could have never published Minecraft; the graphics alone would have sent them running. Look at QWOP and GIRP and Too Many Ninjas: the graphics are terrible even by Flash standards, but they're addicting as hell.
As a gamer, all I can say is this: I don't care what your game looks like, I care how it plays. If you can make something that stands out in this tired market, I'll buy it. The major production houses aren't your enemies, they're your friends: they're the ones putting out the endless stream of repetitive crap that will make your game seem great by comparison. Just don't try to copy them.
I was going to disagree with you but I think you nailed it. Make something that people (i.e. most people) have never seen before. But that's not saying make something that nobody has seen before, just something that the people you're marketing to have never seen before.
That is, I think the key technique for success in any game market (indie or mass market) is to take a gaming experience that's proven to be fun and make it way more polished and accessible (I left out the Zynga games to save space):
Infiniminer => Minecraft
Tower Defense => Plants vs. Zombies
Guitar Freaks => Guitar Hero
The Game Maker => Game Dev Story
Boom Blox/Crush the Castle => Angry Birds
Rogue => EverQuest => World of Warcraft
DECWar => Galcon
Narbacular Drop => Portal
Herzog Zwei => Dune II => Warcraft
Dwarf Fortress => ???
Someone fill in that last one. It'll be tough, but you'll be a multi-millionaire. If you have this many people obsessed with a text mode game in 2011, there's something amazing waiting to happen.
I agree that Minecraft isn't a wholly original concept, but the other examples you cited aren't from "lean" game studios. Your advice to incrementally improve upon previous successes (your own or others') is a good strategy across the game industry, but probably less so in indie / agile studios, where having less to lose allows designers to take more risks with their work.
I think championing the gameplay of an obscure (maybe even non-electronic) but fun game is a pretty significant risk itself.
I've been an IGF judge and I love original gameplay, but I also know that almost everything really is a remix when it comes to game design and that there is more fun gameplay that has yet to find its audience than is generally acknowledged.
If you're trying to fulfill your artistic goals, I understand that originality is its own goal. If you're creating a game because you want people to enjoy playing it, maybe you should start from fun.
Gaming is not a new field, and I think that it's a mistake to apply web startup ideals to an industry with many well-established success stories over 3 decades. All successful development houses got their start the same way - they made a great game that people loved, then another. When Gabe Newell started Valve, he looked at the Quake II's of the world, and said, "this is stupid. The last game had a double-barrel shotgun, so you put 4 barrels on this one and call it an improvement?" They made a great game by focussing on gameplay and the players' experience.
The key seems to be that while the major publishers focus on graphics and production value, the upstarts focus on gameplay. EA could have never published Minecraft; the graphics alone would have sent them running. Look at QWOP and GIRP and Too Many Ninjas: the graphics are terrible even by Flash standards, but they're addicting as hell.
As a gamer, all I can say is this: I don't care what your game looks like, I care how it plays. If you can make something that stands out in this tired market, I'll buy it. The major production houses aren't your enemies, they're your friends: they're the ones putting out the endless stream of repetitive crap that will make your game seem great by comparison. Just don't try to copy them.