It is one big touch screen.As mentioned, should have been one big ( touch ) screen. Doesn't hinder 3DS compatibility ( per se ), but introduces a world of potential.
I understand why they kept the case covering those areas of the screen that aren't going to be used. Nothing would display there and people couldn't really interact with them like they would expect to.Curiously, the 2DS is even more of a tablet-style system than it appears at first glance, as it actually features a single large screen in its center, not two separate ones. As one of their cost-cutting design measures, Nintendo reduced the number of screens in the system from two to one, and the appearance of separate screens is merely simulated by the way the case masks out the extraneous portions. This means the entire screen is by necessity a touchscreen, with the upper screen protected by a layer of plastic that sits above it. While this makes no difference for the system's normal functions -- after all, neither the system's firmware or its software would recognize the hidden, inactive zones of the screen or the upper portion's touch capabilities, even if you exposed those portions -- I'm curious to see what hardware modders manage to do with the system.
That being said, a new system with a vertically oriented screen like that would be awesome.