I see about 1,200 on gamecenter leaderboards.. Tho I didn't see a gamecenter button in-game, or maybe I missed it? Anyways - for these type games, having a gamecenter quick link in-game would be nice. Also, have some goals... Like bronze, silver and gold depending how well you do.
Interesting concept , think I seen other app games that are similar.. not a fan of the font either