I don't use "button masher" as a cheap label for an antiquated genre. I use it in the most literal sense, because this is an iPhone port of Hudson's famous Shooting Watches.
History lesson: Hudson talisman Takahashi Meijin (aka Master Higgins) got kinda famous in the 80's for being able to press a button 16 times a second. Which is pretty awesome. Anyway, to cash in on this, in 1987 Hudson released something called the "Shooting Watch", which let you try and match/beat Meijin's score by calculating how quickly you could press its buttons.
It's this Shooting Watch that's been ported to the iPhone (and is going for $0.99). It's not going to work anywhere near as well as the real deal - no way the iPhone's screen can register that kind of frenzied button mashing - but that doesn't matter. It's a crazy port of a crazy game-related thing invented by a crazy man, and fully-functional or not, that should bring joy to your life, if only for a day.