There is a leaderboard, although its not very obvious. If you tap your high score on the main menu (top right), you'll see the Gamecenter leaderboard.
I know I already commented, but I thought I'd just jump back in this thread because I saw your game featured on the App Store and wanted to say well done. Definitely deserved. I was wondering if you have any other updates planned? Anyway, good luck
Thank you so much! I'm actually submitting a new build for review. This new versions adds a ton of improvements like new enemies, obstacles, bosses and even more power ups. I also added a randomizer button that allows you to re-roll the power-ups for coins!