The Toughest Game I Ever Played

So I picked up the new Deus Ex last night, which is a surprisingly punishing game. Get shot at for about three-quarters of a second, you’re dead.  Then, a long load screen. A better deal than most people getting shot at for three-quarters of a second, but still.
Then I encountered The Impossible Mission.On the third goddamned level.
See, you walk past two cops to infiltrate a base full of mean guys who have taken hostages.  Your goal: to gain control of the base.  And Deus Ex is famed for the flexibility of its missions, where you can go in guns blazing, sneak, or hacking. They even gave me a choice: do you want a real gun, or a tranquilizer dart?
Of course I chose the dart. I never like killing people if I can avoid it.
Except this mission offered me no choice.  I walked past the two cops, into a small hallway that made a right-hand turn – and there were three bad guys just standing there.  I tranqued the first one, who sagged like a sack of potatoes – but the second guy had full combat armor.  My darts bounced off his skull, and he shot me.  To death.
I tried tranq-darting him a couple of times, but no; his armor was invulnerable to my piddly darts. What kind of stupid fucking level design is this?  Give me a weapon that doesn’t work?
Maybe I’m supposed to sneak past. I investigated every corner of the run-up hallway for ducts to sneak through, hidden weapons to use.  Nothing.  My only option was to run into these three guys, all standing to face me, and get shot to fucking death.
Maybe if I ran past real fast… Nope.  Dead.  This reload screen sure is long.
After an hour, I pulled up a walkthrough. The walkthrough, stupidly, started after this trifecta death squad!  What the fuck?  I mean, the game’s only been out for two days, but you’d think someone would have provided hints as to how to get past these three beefcakes here. Who designed this fucking level?
Ninety minutes in, and a lot of screaming, I decided that maybe the invulnerable armored guys had a weak spot in back I was supposed to shoot – which seemed unfair on an early level, since they had their backs to the walls and were facing me, but still.  So I crouched to hide – well, as much as I could in full light – and crept, slowly, around the far wall to look at the guy’s backside.  Maybe there was a quick-kill option if you got within range.  But the AI on these guys was monstrously stupid – here I was, creeping past an unconscious dude seven feet away, and they don’t even look at me.
I get within arm’s reach, and…. a dialogue option appears. And light dawns over Marblehead:
These aren’t the bad guys.
They’re the second row of cops, there to escort me into the building.
Well, maybe they shouldn’t fucking shoot to kill the first time I tranquilize one of their guys. Or, you know, say “WHAT THE FUCK, CYBERPUNK” as they fire. Regardless, I realize the toughest mission in this game, the true unbeatable level, is the one where I decided to betray my covert organization on my first mission.
Well done, Steinmetz.  Well.  Done.