I am a good weapon finder. I found two halo 2 weapons, and one spinter Cell Double agent weapon/grenade. On the level Ellisworth Pantinaty(the one when your in jail) After you kill or knock out Barnam and you end up in a cell. After you get out instead of going left go right and you will find a dead end. At left end of the dead end(lol) there is a smoke grenade.
Every other website has the xbox endings mixed up with the other platforms. I tested myself their method which is wrong and I have found the right one. The 3 endings are of the news report shown during the credits which is very disapointing.
On the mission before the last (cant remember the name) Good ending: disarm all three bombs Average ending: only disarm the one going to the presidents location Bad ending: don't disarm all three bombs and have them sent