When the Mexican gets a crossbow shot in the groin, there's no blood. By the time he covers his crotch, there's a patch of blood already there.
The blood around the black soldier's mouth disappears, before he gets blown up.
The blood on Schweinhart's back, after he gets shot.
In the finale one of the female characters gets shot in the back, for a moment a bloody wound can be seen. A second later when the camera films her from behind, the wound has disappeared.
When the black soldier explodes from having a grenade shoved into his mouth, no blood or guts splatter on anyone from the explosion.
After one of the militants comes racing out in a swamp boat and shooting, the group walks away even though they're in danger.
After Laurie gets shot, she falls over and her hand casts a shadow - presumably from the camera.