Get 50000 points and all 007 medallions for level 2

  

Successfully complete the Fire And Water level with a "Gold" rank.

Beat level 3 with 70,000 or more points

  

Successfully complete the Poseidon level with a "Platinum" rank and all 007 icons.

In the town where the boxes <near the back of the town>are,
  there's a small box then  a medium one, then a  big one.If
  you jump on the smallest then the medium one then the biggest, theres
  a ladder and after you climb the latter there's a small platform and
  from there you can jump on to a roof and it's an  excellent
  snipers position!

  

  Get a mal-22 and grenades on first level

  This is not really a cheat but it will help.First you use your Q-claw
  and go on top of the building and just keep on walking until you find
  a hole.Sneak up behind the guy and karate chop him when he falls a
  keycard will be on the desk.Then you forward and go through the door
  and  another door is right in front of you.Get the keycard out
  and hit a.

      

Successfully complete the Fire And Water level with a "Platinum" rank and all 007 icons.

Get 130000 points for level 11

  

Successfully complete the Precious Cargo level with a "Gold" rank. To do this easily, aim
carefully and shoot the men out of the helicopters to get the gold medal. Also shoot the
gasoline tanks at the roadblocks and shoot the gas station's pumps.

Get 70000 points and all 007 medallions for level 4

  

  Get golden accuracy

  Get 70000 points for level 4

  

Successfully complete the Streets Of Bucharest level with a "Gold" rank.

In the second level when you reach the road block where there are two
  cars on the left, an armored truck in the middle, and a hilicopter
  hovering on the right, just shoot a rocket at the tank in the middle
  and it will blow up all of the vehicles.  You might have to shoot
  it two times.

Successfully complete the Forbidden Depths level with a "Gold" rank.

In the First mission there is a locked armory to the left if you went
  in the front door, it contains grenades and a bazooka.  To get
  the key card enter by using the claw on the vent outside, at the end
  of the catwalk you will drop down and see a guard facing away. 
  Drop in, get right on top of him and hit him with your fist, he should
  go down in one or two hits and you will get the key card if you're
  close enough.

  

  Secret Floor

  

  In the level Bad Diplomacy, when you go into Griffin's office you kill
  him, then use passcode generator on the computer. Then go back to
  Griffen's office the door on the far right hand side. If you use the
  "Key card" you use to get in originally then walk in. HURRY!
  you have to shoot the officer first.You will see the laser. Go to the
  right wall use your Q-Specs and you see a little door, open it. Use
  your Q-Laser to disable  the laser. Get ready to kill 2 officers
  then don't worry there is a elevator to take you to the exit of the
  embassy. This will give you your last Bonus point to get 7-7.

  

Get 100000 points and all 007 medallions for level 8

  

Successfully complete the Forbidden Depths level with a "Platinum" rank and all 007 icons.

Get 100000 points and all gold medallions for level 7

  

Successfully complete the Night Of The Jackal level with a "Gold" rank.

Get 130000 points and all 007 medallions for level 12

  

Successfully complete the Dangerous Pursuit level with a "Gold" rank.

In Bad Diplomacy when you get outside to climb up the latter instead
  go out all the way to the rail and look up behind you you will see
  something like a speaker use your claw to get up there and you have a
  Bond move