Console Version Differences
The most common version for Nightfire speedrunning is the Gamecube version, but any version of the game is fine to run with. It is recommended that you play on the Xbox or Gamecube version since they have faster loading times and less lag than the Playstation 2 version. Aside from that, there are no major differences in gameplay between each version.
For full-game speedruns, timing starts when you gain control of Bond at the beginning of The Exchange and ends when "Mission Complete" appears on Equinox.
For Individual Level speedruns, simply refer to the in-game timer on the results screen. Pausing the game is not allowed for Individual Level speedruns since it can cause the in-game timer to be inaccurate.
Console: The best control schemes for speedrunning are ones with Move/Strafe bound to the Left Control Stick and Look/Turn bound to the Right Control Stick or C-Stick. The names of these control schemes vary depending on what version of the game you're on but they all function the same way. On the Gamecube version, the best control schemes are "Nightfire", "Moonraker", "Goldfinger", and "Goldeneye". These control schemes are better for speedrunning since they make it easier to move optimally.
PC: The PC version has no specific control schemes. You can edit whatever actions you want to whatever keybind you want.
Console: The fastest way to move in 007: Nightfire is to strafe forward/left or forward/right at a 45 degree angle. Optimal strafing is much easier to do with the GameCube controller since it has notches around the control stick in 8 directions. Holding the control stick in the top/left or top/right notch is the easiest way to move optimally.
Note: Sometimes the alignment for GameCube controllers can be different. If holding up/left or up/right makes you move very slowly and to the side, move the control stick a little more forward until you notice a large speed increase.
PC: The fastest movement is to "Power Jump" (or "P-Jump"), which is essentially gaining momentum from side jumping and moving your mouse. I very detailed tutorial can be found here.
The fastest way to go up stairs is to jump onto them and mash the jump button all the way up. Stairs will normally slow down your movement but pressing the jump button will allow you to regain full movement speed for a very short time. It's not known how exactly much time this saves throughout the whole game but it likely saves a few seconds depending on how fast you can mash. This is a console only thing and does not save time on PC.
Clipping is, by far, the most useful technique in the speedrun. It allows you to go through walls and floors that you could not otherwise get through and it also allows you to get out of bounds almost anywhere in the game.
Before you can execute a clip, you need to crouch and switch to your fists. Then simply uncrouch and pull out a weapon or gadget and the same time. You will notice that Bond stands up a little bit then immediately pops up into a full stance shortly after. During this time if you move under an object that would prevent you from uncrouching, you will store a clip. Simply crouch again and you will fall through the floor. This is also a console-exclusive strat.
A more detailed explaination of this glitch can be found here.