In the 25th minute marauders are robbing tents. When Simon, Jessie and Andrew went to sleep in their tent, no other tents could be seen anywhere.
In the 38th minute, Simon's black eye from the previous night's fight has dramatically changed and miraculously healed.
The license plate pictured in the 19th minute is from Maryland. It is missing a slogan at the bottom.
In the 66th minute of the movie, after working the day in the sun, none of them are particularly sweaty.
Upon returning to the campground after the marauders have left, it seems odd that none of the three check to see if any of the bodies of other campers is alive.
When Simon fixes Andrews car, he says it was a loose wire between the battery and starter. If that was the case, the starter would not crank, and it does. It does not turn over, but the starter does crank.
Upon returning to the campground after the marauders have left, it is unclear why they did not take their tent for the journey.