This trailer has me rather excited, which is unexpected.
I have watched some L&O episodes, but never really got into the series. But the concept was neat, and that is obviously transferred to the game. Also, this is the one type of adventure adaptation where "losing" actually makes sense. It's quite often that in modern TV courtroom drama series, the lawyer protagonist is allowed to lose the case - because he's been played, because personal matters have impaired his ability, because an impractical US law prohibits him from presenting that one final evidence or because it might become evident during the prosecution that the defendant is in fact innocent. Some of these endings are shocking, but mostly make for a satisfying ending of a TV episode. I am curious as to whether this might work in an interactive medium, where "winning" must be perceived as a far stronger impetus for the consumer. Watch your endings there, TTG!
This is also what might put the "You don't have to be a gamer to play it" into context. You're making decisions in a story, you don't necessarily play to win.
Graphic style: I'd say it's a win. This is obviously mainly designed for the mobile devices, so some limping is to be expected. Something still strikes me as quite not right in the trailer, but I can't really say what it is. Something I can name is that the choices presented block the entire screen. Ahhh, don't do that in the PC version, please. I know that mobile enthusiasts are enamored with getting their fingers everywhere on the display, but we PC players want to see a bit more of the characters during conversations.
Whoops, post was longer than expected. Gottago.