Although the MacBook Pro with Retina Display is my main computer, it spends most days tethered to a Thunderbolt Display. Mini Display promises the luxury of dual displays from anywhere, as it's a universal app that extends a Mac desktop onto an iOS device on the same local Wi-Fi network, but it’s not yet ready to replace the real thing. Avatron’s Air Display, which has been around for quite some time, actually does the same for a few dollars less, and works with both Mac and Windows.

Most platform games are known for their difficulty in having players master the art of running and jumping over large gaps and onto hard-to-reach platforms. Taking this concept and turning it on its side, Illusion Labs’ latest game is a vertical auto-running title that simply requires you to know when to jump. Mr. Crab’s controls may sound easy, and its colorful visuals might seem a bit pre-school for some, but this friendly crustacean offers plenty of challenge to keep players of all ages coming back for more.

Sparrow may have blazed a trail for acceptance of third-party iOS email clients, but there’s a new kid on the block: Mail Pilot, a universal app that attempts to infuse slick organizational talents into traditional IMAP email. Mail Pilot’s creators should be applauded for native iPad support out of the gate, a feature still missing from popular alternatives like Mailbox. For those who spend their evenings at home with the iPad, the ability to move between iPhone and tablet at will is a big plus. Sadly, IMAP compatibility issues make this pricey app a tough recommendation.

Take the electronic stylings of the cult Swiss electronic band Yello, stir in the visually interactive approach of iOS, and you’ll end up with something as profoundly cool as Yellofier, a free app for taking sampled sounds – including your own – and turning them into radically cool and wild musical passages. A commercial app of this depth and breadth would be a revelation, but for free, it’s just short of miraculous.