It's pretty much exactly as I speculated in some other thread that may not even have been here.
The simulation is an old army training thing that the brotherhood outcasts have discovered at an old army facility underneath downtown DC. They're there to get into the armoury but it'll only unlock for registered personnel and the only way to fool the system is to complete the training sim. You don't get to keep the exact weapons and things you get in the sim (in fact the enemy disintegrate when you kill them, the program basically de-spawns them so you can't pick up as much) but get to loot the armoury after the sim.
The slick gear includes the chinese stealth suit (basically combat armour with +15 to sneak) the chock sword the chinese general (who i talked to death) was carrying and the very nice Gauss rifle (an energy weapons based sniper rifle I think) which is very expensive to fire, a full microfusion cell per shot! The way you get it is that there's one of each in the armoury when you finish the training and you can pick & choose what you want.
The sim itself is set up like a game, there's health & ammo stations around the place and interactive objects are highlighted in orange, sort of like a COD style look. I'm not sure if I like that as a bit of a pisstake of overly helpful FPS' or dislike it as making it a bit simple. They handle the invisible wall thing quite nicely, the program was clearly made for a limited area and when you approach the edge it gets all pixellated & blue to indicate the end of the area, sort of like how assassin's creed did it (though without the arbitrary 'unlock this area' job which always sucks)