The movie ends with Megan, Burrows, Paul, and Frank moving toward the city; however, the movie reveals that some zombies, including many other zombies moving toward Missouri's wilderness area, have survived.
The movie ends with Megan, Burrows, Paul, and Frank. The movie is moving toward the city. Some zombies have survived. This was including many other zombies. This is what the movie reveals. These many other zombies are moving toward Missouri's wilderness area.