Regardless, I think it's best to begin smaller first, make a bunch of quick and simple games with interesting or even banal mechanics until you tackle something bigger like a survival game.
Tip: Go to any gaming forum on facebook and some other create polls or give a poll option to fill that would be great because you will get a lot of ideas because people will seek to vote on your poll. One thing: Think out of box!
I've had an idea for a TV Show/Comic that I think would translate into a game well. Post Apocalyptic, after the Yellowstone National Park Volcano, erupts. Inside was an old virus dubbed the Ash Virus. This virus spread throughout the entire United States through the ash cloud the volcano created. The victims of the ash virus would then begin experiencing body decay, and extreme reflexes. They grow lumps all over their body until eventually, they become blind, their senses get tuned and they can hear anything. You could have the player hide from these creatures, trying not to make noise while surviving.
