This was the Season 2 finale. We may or may not get a Season 3. But that's okay, but this ended in a satisfying spot. [spoilers ahead]
I'll admit to getting a tad annoyed with the Lost-like stuff. More purgatory/afterlife. Yes, it was true to the story that had been set up (rather than being somewhat random as it was in Lost), but it felt like a re-tread. A we-did-this-once-before kind of thing. Because we'd seen Kevin die and come back, like, just a couple episodes ago. Never mind seeing all the afterlife stuff on Lost a few years back.
That aside, however, I was pleased with the way things played out. Though I did wonder about why one would bother with a countdown clock. Doesn't that just give law enforcement time to thwart your plan? If you're going to blow something up (and yeah, I know, they weren't), you just do it. You don't give people time to act against you.
Not that it seemed like anyone was doing much to stop it from happening anyway.
Overall, though, I enjoyed this season more than the first. It simply had more of a coherent story. It had the supernatural element turned up a bit, too. Some people might not enjoy that, but I felt like there was just the right amount of it. The kind of "weirdness" you might run into once or twice in life without being able to explain it. Well, except coming back to life. You don't run into that much (in my experience).
While I can hope for more, I simultaneously worry they'll ruin it if they push it too far. You know how it is when a really good show that you like tries to squeak out a couple more seasons. It sours. We don't need this to go X-Files or anything. But if they can get another great story pulled together, well, that could be something to look forward to.