@Gri :
My advice for you would be :
You could achieve your zombie mini game and i'm sure you should not be rich , but gain good money that would at least pay your time and software investment.
And it would just be a start to begin to be known as a good indie game maker.
But only if you are motivated enought , caus making even a small game asks so much energy.

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For Android :
Don't worry , lot of people will stay on Android, because it is open system, and lot of people knows how Apple is expensive and closed system.
It will stay very long time, and just look at incoming "light indie" consoles like Ouya, Nvidia Shield : It's ANDROID.

The advantage is that with mobile market, you don't need to find a publisher to distribute your game.
Even small not so good games made by programmers are sold, even you could sell some game based on levels gameplay.


The other advantage is that mobile don't require models with high res models or textures :
Gameplay, eye candy HUD, and fun are the most importants after a good acceptable design and graphics.

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I searched on Android for not so good games, and believe me there are not a lot, if you can make a good one with not so bad graphics, and good gameplay, there is room for you and us indie people.