During driving scenes and in others, seasons change shot to shot. In some there are no leaves on the trees, in others it is full summer.
In the opening scene, skiers are leaving the resort with their skis, yet it is clearly summertime and long past ski season. The effects crew tried to place mounds of fake snow here and there, but even if it were real, there is no way anyone was skiing a day ago on that mountain.
After Megan gives Rich her Porsche, he "pops the hood", presumably looking for a bomb in the engine compartment. However, Porsche 911s are mid-engine cars, so the engine is at the rear.
During the final shoot-out in the bedroom, you can quite easily see that Corey Haim is wearing ear plugs similar to those use on a test firing range to protect the user from the noise of the shots been fired.
A launching board is clearly visible throwing Rich into the air to simulate the impact of the car explosion.
Rich eluded Cy by jumping from the balcony, then hanging from it. Cy couldn't see him, because the potted plants obscured the view of his clutching hands. But those potted plants would have made it impossible to jump over the balcony at that place.
The USA DVD from Artisan Entertainment says it is the 91 minute R rated version, but it actually is the Unrated 93 minute version.
When Wes accosts Megan though the bedroom curtain, two crew members are visible in the reflection from the window.
As the camera pans to Rich just before he confronts Wes and Megan in bed, the shadow of a boom mic can be seen in the upper right frame.