Plot hole: In the level A Show of Force, Bond has to drive the Q-Bike. It seems that this bike came from nowhere, as it wasn't there the first time he went to the safe house, and 003 was already captured. No one could have put it there.
Other mistake: When Bond and Serena arrive at the mining complex, they see two guards. Serena asks Bond, "What about the guards?" and Bond knocks them out with his dart gun. If you look carefully, you can see one of the guards fall before the dart hits him.
Continuity mistake: In the level Ambushed, after Diavolo leaves the room where Bond is with the two guards, they both have a gun pointed at Bond. But after Bond says "You first", the game shifts to actual gameplay, and the guy behind Bond no longer has a gun.