OK, disclaimer at the start of this, I am a fan of the Metroid series. I won't say I am biggest fan, but a fan none-the-less. So the fact that this E3 was meet with not one, but two Metroid titles, pure 100% awesome!
First title, the big one that was announced during the Nintendo Direct. The tentatively titled Metroid Prime 4. What do we know about this game? It will be for the Switch. And, umm... It will have Samus in it. And that is pretty much all that we know. But there was a pretty trailer for the announcement.
The next game we know much more about. On September 15 Metroid: Samus Returns will be released for the 3DS. This will be a 2D platformer that is mostly a remake of the original Metroid II: Samus Returns with some new abilities.