Visible crew/equipment: In all the President Kennedy White House shots, you can see the boom mic peak down several times. Look for the group shots, and the boom mic will be there.
Revealing mistake: Just after Li Mu Bai tells Shu Lien that they are very close to her headquarters and that she should check in, we are treated to two 'time pass' shots of forest. The second of these features some very obvious power or telephone lines in the lower right corner of the screen. (01:22:40)
Character mistake: Wilhelm Keitel was a field marshal, not an admiral as stated during the sentencing.