Goofs

Matt pulls his car off the road and pulls a lever resulting in a large inflatable tent. He unzips the flap, and there's a circular bed inside as well as a bedside table and fridge. He ushers Sheila in and follows. The inflatable items are now solid, and additionally there are 2 chairs and a radio on the table. Cut to when they're in bed, which is now against one of the walls, and they have proper pillows, and the gold cover is now a green blanket. When seen earlier in the car boot, it was black or dark blue. By freezing the frame, it can be seen that thee are now magazines, a phone, and a camera on the table.

Throughout the entire film, wires used to lift things and people up with the "anti-gravity ray" can be seen. This is especially obvious when the saucer is brought down to the jungle and when Matt rescues Sheila from the runaway train wagon.