When the anomaly appears in the cellar, the cans on the trip wire start rattling, signaling the magnetic field. However there are metal cans next to the anomaly which aren't affected by the magnetic field.
When the getaway car with Danny, Sarah, Connor and Abby evade their pursuers, the pursuing car pulls up short and it can be clearly seen that the letters and numbers on the license plate are mirror-image reversals, showing that the shot is flopped, and possibly filmed in reverse.
Just after Conner is shown attacking the prehistoric birds with bottles of wine, Danny yells at him that the bottles are worth "1,000 pounds a piece". But when the bottles hit the birds it is clear that they are empty and therefore virtually worthless.