Goofs

The size and depth of the river changes dramatically throughout the film. Sometimes they are on a wide deep river, then it becomes narrow and shallow. Then becomes wide and deep again.

When Trevor is firing the handgun it runs out of ammunition just out of frame. The gun is heard clicking subsequently, indicating he is pulling the trigger but without discharging a round. The gun Trevor stole is a semi-automatic handgun, so pulling the trigger once the gun has depleted the final round would result in the slide being in the rearward and locked out position and pulling the trigger would not make the gun "click".

Any reputable commercial rafting company would have a 2nd raft...partly for safety / where 1 would carry the gear and the other would be for the rafters.

Shortly before Trevor and Gray discussed the dead sat phone batteries, Joey was shown in her tent apparently texting with her boyfriend. However, Joey had simply entered a reply and hit send, and her message is shown with an unsent status that indicated she did not have service.

The group leaves the river and raft, hikes into the woods and spends the night along a trail where Trevor ties them up. The next day they end up back at the river and have the raft with them again. If they went back to where they left the raft, what was the point of hiking into the woods? If they continued hiking the trail and it met the river again, how did they get the raft? It's too big to have been deflated and carried in a backpack.