The object of this game is to get as many kills as you can in exactly 2 minutes. Kills are shown on the finishing screen (obviously), the number it shows there is the number of kills you got for that stage. Try to do this on all levels, even Duel.
The rules of the newly created "2 Minute Kill Fest" are simple:
(1) You must play on the "Perfect Dark" difficulty with any settings you like.
(2) You do not have to complete the objectives.
(3) You can use any cheats you want except: Slo-mo Single Player, you cannot use the
FarSight XR-20 weapon.
(4) You must stop at exactly 2 minutes on the clock.
This is not a rule, but is extremely helpful in knowing when to abort the mission. Go into the Options and make sure the dot to the right of "Show mission time" is red, not clear. that way you will be able to see how long you have been playing, and when you need to hurry for those last few kills.