I don't own a mobile phone, but the idea seems pretty original to me!
a "runner" rpg - nice idea!
aesthetically, I think you could probably limit the color palette so it has a more unique "look" - but the art is really high quality. Would be cool to see less "jrpg/zelda" style monsters (jellys and bats are in a lot of 2d rpgs I believe - and with your artwork it would look even more awesome with new and different monsters!).
Is there a story? it would be cool if there was a really nicely written story - so if you ever do a sequel see what you can do there :)
A final fantasy style battle system (simplified, of course) would also make the gameplay a bit more engaging.
but this is just me looking for things to critique as you asked for feedback, it's a great idea and is very polished! awesome job.