The poisonous venom of the snake kills the alien (Rayford Barnes) almost instantly. This happens despite the aliens having no heart or blood or circulatory system to circulate the venom through the body.
David parks his car outside Harry's Bar & Grill, then after the chase and fight with the old man, David walks back into the Bar & Grill and the car is now gone. This then gives Beth the opportunity to park her truck in the same place as she arrives back at the Bar & Grill.
In the opening scene, as the camera pans past the shrine and towards the couple making out on the ground, the shadow of a crewman's head can be seen briefly on the wall.