A perceived problem with iOS as a gaming platform is the lack of tactile controls, which is a particular issue with platform and retro games. iCade Core gives your iPad arcade-style controls; it's battery powered (two AAs) and connects via Bluetooth.
As support for the iCade has to be added by a game's developers, only certain titles are compatible - there's a complete list over yonder.
The one-piece plastic concoction resembles the chunky controllers you used to get on arcade machines, but it feels a little cheap, and lacks the retro charm of its cabinet-shaped older brother. However, it's a lot more portable and easier to store than its wooden sibling, and it succeeds where it really matters.
Again, the joystick and buttons feel great, if a touch softer than the original iCade's, providing plenty of precision control over compatible games. The cradle is sturdy, and boasts a pass-through slot for charging.
It works nicely with an iPad in landscape or portrait, though it does sit a touch low, meaning your hand can block a little of your view. However, as the unit uses Bluetooth, you can always set up the iPad elsewhere.
At £50, the iCade Core is a great value iPad accessory for hardcore gamers.