Trying to beat all of the challenges in the Modern Warfare 2 El Sin Nombre mission? This is one of a handful of stealth sandbox levels in the game and it can be pretty daunting if you’re used to running and gunning your way through most Call of Duty campaigns. Still, even if you’ve ticked this mission off, there are a few secrets and challenges to complete on El Sin Nombre away from the main objective.
For starters, there’s an interrogation sequence to survive, and then you have to infiltrate El Sin Nombre’s penthouse, either by sneaking in through the elevator shaft or stealing Diego’s keycard. If you can avoid killing anyone or triggering an alarm then you’ll complete the Ghost-in-Training achievement, and there’s even a safe code to find on this mission, which you can use to bolster your arsenal ahead of the showdown with El Sin Nombre.