Underground Pixel is a retro game developer that's put out a few iOS titles already, and their latest release is called Mansion Run, now available on the App Store for just 99 cents.
Mansion Run is simple by design -- in fact, it's almost too simple. The idea is that you're a skeleton named Boney Wellington (nice) who has to run through a house full of poltergeisted furniture. There are four levels to run on, and the whole game is that you simply swipe up or down to switch levels, dodging furniture for as long as you can. That's it -- all of the furniture is essentially the same, and none of it ever moves. Just run and dodge.
That simplicity may sound a bit off-putting