There is no magic number! Hype comes with people liking the idea and SHARING it.
No offense, but I'm pretty sure that your graphics are the reason you don't get the attention you would like to get.
Gamers are one of the Graphically most sophisticated audiences. Gameplay ideas don't really count in there eyes if they aren't visually supported:-)
Just my two Cents! Good luck with your game, as always mate!:-)