Episode 2 is nostalgic and fun, continues the series in good form.
Most of this episode takes place in 1931 again, although there are a couple segments in other time periods. Hill Valley is shown mostly at night or dusk in this episode, which gives it a slightly different (and better looking imo) look than in episode 1. We also get to see some new locations as well that all fit in and work well to develop the town.
As I'm sure you've heard the voicework in this game is very good. Some are better than others, but Marty's voice is spot on. The guy who does that voice is almost like a vocal twin to Michael J. Fox. Doc's is Christopher Lloyd of course, so no worries there. The music uses the familiar BttF themes well and goes along way to carry the nostalgic feeling you get while playing.
Gameplay is the weakest element, unfortunately. My biggest complaint is that this game is so easy, it almost borders on going from "adventure game" to "interactive movie." There are puzzles, of course and a few of them may make you stop and think for a minute. Just don't expect any brain twisters. Most of the time, in fact, the game basically gives you a puzzle and then points you directly at the answer.
There are some bugs too, nothing game breaking I assure you. Mostly just typos and some mild graphical weirdness. I witnessed a few but it honestly did not take away from the experience. If you've ever played a Telltale game before you might actually have some idea of what I'm talking about, since this seems to be a common thread in their games.
Whatever platform you get this for, I think its a really good deal. If you're a fan of the movies this should be a no-brainer. The story and nostalgia more than make up for the shortcomings.