I still need to be careful about what I say at this point, but since that non-final box art has been leaked, I can at least provide SOME clarification to the obvious speculation.
Yes, it's a portable Atari Flashback with SD card support. That means you can add your own Atari 2600 games as long as they don't make use of special chips or other features in the cartridge (e.g., Pitfall II).
No, it's not a NOAC. AtGames never has used a NOAC and never will. It's a new generation of the same proprietary hardware that has appeared in previous Atari Flashback products.
Frogger is just like Space Invaders, i.e., a newly created port that takes advantage of the Flashback hardware and is not Atari 2600 compatible. Like with Space Invaders, it gives you an arcade-like feel, but is not a 1:1 match of the arcade and doesn't play exactly like the arcade (AI is different, etc.).
I'm very happy with the button layout. It recreates all of the functions of the heavy sixer (plus the fire button of the joystick) in a logical layout, plus adds portable-specific features like Pause and Menu buttons. I specifically wanted all of that to maximize game compatibility.
The emulation and screen are quite good. There's also TV out, although like with the Sega product, you have to purchase the cable separately.
Hopefully we get the press release out soon and I can discuss this more.