Other mistake: There's no way for Shelly to fit his masks, a speargun and other items in the small box.
Suggested correction: No, but we don't know exactly what he might have brought. The first time we see him they're picking up Vera, so it's most likely he brought another bag that could contain the items. He only said to Vera that the small bag was his whole world, but he just met her (Andy mentioned he got him a date for the trip) and he's trying to get her to warm up to him.
Creating a series of theories for obvious mistakes/plotholes never resolves them. The fact that Shelly managed to fit all of his belongings in quite small box is too confusing because he is never seen with another bag/box.
Doesn't mean he didn't bring anything else simply because we never saw him with another bag. There may be no way to get everything into the tiny bag we see him with, but we also never saw bags carried by Chili, Chuck, or Rick. Does that mean they didn't bring anything with them for the weekend?
And stretching your imagination is often required while watching a movie so one doesn't have to create 'obvious mistakes/plotholes'.
The correction submitted by Dewinela is not "creating a series of theories." It is quite plausible that Shelly packed his items into more than one bag. Do you think he would have stood there and pointed out each bag to Vera - "My whole world is in this bag, and also this bag, and this bag..."? An awkward character, with low self-esteem, simply gave a poor description.
Thanks.
Other mistake: When Harold is going "Number 2" on the toilet, you can hear his crap plopping into the toilet water. However when he is making his search in the bathroom, he walks by the toilet and there is nothing in it. The toilet is clean. He never flushes it before making his search.
Other mistake: On the back cover of the DVD it says "An idyllic summer turns into a nightmare of unspeakable terror for yet another group of naive counselors." The cast of this film are Chris's friends, not camp counselors.
Other mistake: After Jason slashes Andy in the hallway we see the machete ripping down through Andy's abdomen as he is upside down in his handstand. Then his body falls to the floor and Jason starts dragging him, but there is no blood spatter anywhere on Andy's chest, face, or the floor.
Other mistake: When Chris finds Shelly "pretending" to be dead, if you look as she opens the door, you will see the door lock on the knob is outside the door, not inside.
Other mistake: The whole time Debbie is in the shower, she only washes her chest, arms and stomach. She's always mostly just washing her arms over and over. (01:01:25 - 01:03:45)
