Could have been a great movie IF..... (*SPOILERS*)
...they just gave a little bit of a damn premise! After reading Wikipedia and learning that they are all in Purgatory and the creatures are basically overseeing and judging whether to drag you to hell or not, it makes for a pretty bad ass movie! They are all caught in an endless loop where until they finally "learn their lesson" they are stuck repeating the day's events.
As we saw, the hospital guy "repented" in some way and was allowed to move on, most likely to heaven. Jack and Mitch (the dudes in the truck), Jack didn't "repent" and was killed and sent to hell, and Mitch who hadn't come to any resolution was thrown back into the loop.
I just don't see why filmmakers have to keep playing this "figure it out for yourself" crap! I mean, they don't have lay out the whole thing for you, but this isn't some Hollywood blockbuster I care to rewatch again and again until it all makes sense.