“What’s the difference between the Nintendo 3DS and the new 2DS?”
2DS and 3DS differences in a nutshell:
No 3D compatibility (hence the name 2DS)
No claim shell design just one solid slate
Directional Pad, thumbstick and buttons have moved up
Mic has been moved to the lower left
Two shoulder button sits on top
But just like the Nintendo 3DS:
The same dual screen style
Comes with a stylus
Camera for shooting images in 3D
Software such as the Nintendo Shop
The 2DS will play your 3DS games and most DS games
So the only obvious difference is the clamshell design and the lack of 3D-viewing of games.
2DS Introduction Video: