Good luck!
Hmm... hey, if you want to appeal to as many people as possible, perhaps you could do something similar to what Era was originally going to do. It'd be cool if you could at least go back and forth between an ancient age of magic and a future of powerful technology.
I dunno, it's just something that'd tickle my fancy at least. I'm not saying shoehorn guns into the gameplay, but things along the lines of powerful technology could include things like, say, a wrist mounted weapon that taps into the user's nervous system to project amplified bioelectricity. Stuff that's more sci-fi, that takes the place of magic essentially.
Still, do what you want, and I hope you find success