Something is troubling Lullaby. Could it be this app?

Ruben & Lullaby is the best of apps and the worst of apps. After a few minutes with it, we can honestly say that it manages to be both an extremely inventive experience AND the dullest app in the iTunes App Store.

Characters Ruben and Lullaby sit on a park bench, having their first romantic quarrel. Shift your iPhone to the left or right to alter the point of view between each lover, and touch the screen to change the character’s line of sight. If you want to enrage a character, shake your iPhone. If you want to give comfort, stroke the screen. Depending on your actions, you can choose whether or not to reconcile them. (Click here for a demo.)

And that’s all, folks.

The idea that you can affect character emotions through the iPhone’s interface is so intriguing that we can’t help but be impressed. The comic-style graphics are charming, and the background music will appeal to fans of cool jazz. However, Ruben & Lullaby is limited to less than ten minutes of entertainment. For $2.99, that’s not good enough.

So whether or not you would like Ruben & Lullaby depends on what you’re looking for in an app: those looking for a thought-experiment will find themselves happily rewarded. But players looking for a game would find a tic-tac-toe app more enduring.