Extra Guy writes: Apparently the best idea right now is to produce a Minecraft clone. I don’t know the first thing about that game or its variants so I can’t help you there. The two top-downloaded games are Total Miner: Forge and FortressCraft so at this point anyone that can do about the same or better is pretty much guaranteed at least the #3 spot. I did attempt to play Total Miner and can best describe my experience as “bewildering”.
The old standbys like Avatars and Zombies have their place but their prominence is dropping rapidly. Going by the last 50 releases, I think there have been less than one Zombie and only a few Avatar games in the mix. The next big fad might be just around the corner though so keep plugging away.