When West shoots the grappling hook up the cliff face, the hook is gold colored and has two hook arms (barbs) like a large arrow-head. When it just clears the cliff edge, it is smaller, silver, and has three or four barbs.
When West first meets Sanchez, after Sanchez rebuffs West's toast, West picks up his drink with his right hand, but in the next cut, it is in his left hand.
When West fires the grappling hook up the the cliff face the rope he climbs on is cheap heap. Hardly the kind of rope one would choose to risk ones life on. Furthermore, the diameter is too small to grip properly and allow hand-over-hand climbing. The occasional knot would seem rather useless. Given other episodes where West uses cable and a mechanical winch it seems odd that he'd rely on such a low-tech solution. And he doesn't even use his leather gloves to protect his hands.
When Jim pours the acid on the lock holding Artie's stock closed, you can see the wood grain in the "jade" stocks.
When Henry Johnson sets his rifle against a rock, it resonates with a hollow thud, showing it to be just a prop.
When Jake throws 'coffee' in West's face, it is obviously water, and is also not hot, as there is no sign of burning on West's face.
The bottle of whiskey that Dr Johnson (AKA Mallory) has froths up. BUT whiskey does NOT froth up when shaken! However, tea does, revealing the true nature and content of this bottle's liquid.
When Jim pours acid into the lock
on Arte stock a wire can be seen pulling the lock open.
The position of the moon would change depending on the time of the year, as well as the cycle of the moon.