The 2DS will play all the software the 3DS can (again, without the 3D). The slab-shaped device has no hinge and only one screen divided by a plastic overlay. All in all, it uses less (or cheaper) parts so it can retail for a low $130 USD.
My gut reaction was that this is pretty dumb. Apparently a lot of people on the internet did too. But that doesn't matter. Why?
Because it's not for those of us who already have a 3DS. It's not for people who were on the fence about a regular 3DS, because we want to carry it everywhere and have a paycheck.
Every 3DS game case has to warn parents that children under 6 shouldn't use the feature...except this one doesn't have the option of 3D. The lack of a clamshell design means there's no hinge to break. And the low, low pricetag means parents will be more inclined to pick one up. It's no mere coincidence this is coming out the same day as Pokemon X & Y: Nintendo has finely tuned the 2DS for the young child demographic.
And then there's anyone who doesn't care about 3D (pretty much everyone), anyone who won't let the lack of a clamshell design slow them down, and anyone who likes the lower price point (again, pretty much everyone).
I wanted to do something making fun of the 2DS, but I honestly do think the will sell really well. That's not to say it's exempt from commentary, but that's a different comic for a different day.