Got a quick yes/no question, is it possible to get out of UNATCO without killing Navarre? And if so, does it require glitching the engine like in the original, or is there a designed way to do it?

{no details needed, I'd like to figure it out myself assuming it is possible}

No, she is the only required kill.

No no, the non-lethal achievement allows her to be the only kill you make.

Hm, not for me. Unless the killphrase is the only way that is recognized.

It counted as a kill for me too, when I finished her, Hawkbird is incorrect.
I couldn't test the kill phrase, my game bugged and Denton wouldn't talk with her.
I tried many times, to exit the facility without causing her death, I even did the same thing a video showed in YouTube, which was to throw LAM near her and run the corridor, and quickly press the door button. But nope, the game wouldn't allow me to escape.
To not fail the achievement, I used the console command: 'ghost'. It was the only thing that worked, to keep her breathing and exit the building.

I'm not sure what to say. I don't have the GOG version but the files should be the same as the Steam version. I just tested on Steam and it didn't fail the achievement for me. The code explicitly allows you to kill Anna and not fail the achievement.

If you were talking about Steam version, you should've pointed that out earlier, don't you think? Everyone reading this thread would think you're talking about GOG version, we are in the GOG subforum of DX, after all. I was playing GOG version and thought you were right.
Why would anyone come here specificaly to talk about Steam version, if they can go to Steam forum? Steam version is irrelevant to this discussion.
It's irrelevant if Steam version allows you to assassinate her and be able to complete the achievement. I say 'if', because it seems unlikely the developer would remove that ability from the mod, and I'm a bit sceptical about your post, how would I know you're not trying to put blame in something else?
You were spreading false information to the OP, there's no denying it.
I know very well it wasn't your intention to fool anyone, but be more careful next time.

I am the developer. I'm the one that coded all of the achievements. I come here to try to give support to anyone that owns Revision. I know that I should have a copy of the GOG version of Revision but I don't own a copy of the base game here.
I say that it should be possible because the GOG version of the game uses the same .u files as the Steam version. There's a bit of a difference between the versions in that the Steam integration is removed and replaced with GOG Galaxy support, but all the UnrealScript code should be the same.
When you say that it doesn't allow you to assassinate her does that mean that the "Achievement Failed" message pops up? Because that should only popup if you haven't failed the achievement so far, which has these conditions: they weren't a robot, they weigh as much as a dog or more, they weren't knocked out, they were killed by you (or something that doesn't have a killer tied to it so it seems to default to the player (such as MiB/WiB/Mech explosions, turret kills), they weren't already dead, you're not playing on Survival, and they weren't Anna.
Anna should absolutely not fail the achievement, unless when you kill her she explodes and takes out someone else with the blast. I just retested (again, on the Steam and my developer version) and killing and/or using the killphrase didn't void the achievement for me.

I just bought the GOG version of Deus Ex and launched Revision. I killed Anna and it didn't void the achievement for me. Are you talking about the Steam/Galaxy achievement (The Unavoidable Sacrifice) or the Biomod Non-Lethal challenge (or something else)?

Hmm, I wonder why GOG didn't give you a different style, developers have different font color than the rest, and they have a "Developer" bellow their avatars (for example, Stardew developer). Strange.
Anyways, yep, the message appears on my screen, telling me that I ruined the achievement, and when I pause the game and check it, it shows status "Failed", in the screen that lists all challenges. It happends every time I kill her, with melee or ranged weapons.
I not playing on survival, and I didn't kill anyone (anyone that counts as a kill I mean. I destroyed that vacuum robot in UNATCO base) before that. Some humanoid enemies died, but not by my hands.
There was times where I acidentally killed a person, but I immediately reloaded the game when that happened.
I just tried again, I killed Anna and made sure no one else was hurt by me or the explosion, and it still makes me fail the challenge. I don't know what might be causing this annoying bug.

Are you playing on BIomod? That sounds like the Biomod challenges system (which you view from the main menu I believe). Because that's not a system that I developed and it's completely unrelated to the Steam/Galaxy achievements, i.e. failing non-lethal challenge in Biomod may not mean that you failed my version of the achievement.
If the message you get says "Challenge Failed: Non-lethal" then it's the Biomod challenge you're referring to. If it says "Achievement Failed: The Unavoidable Sacrifice" then it's my achievement.

As for the requirements for that challenge, they are failed if you are the killer, they aren't stunned, and they are human. I'll admit I haven't played Biomod past testing (I know right) but it seems here that Anna is immune to things that knock her out. Not sure how you're meant to get past her, but I've seen people who have completed all the challenges. I'll see if the killphrase is allowed.

That seems to be it. Using the killphrase on her doesn't fail the non-lethal challenge in Biomod.

As for why I don't have the developer style/font, I've admittedly never used GOG outside of Revision, and I never contacted GOG personally in regards to Revision, someone else on the team handled professional communications.

Oh I thought challenges were already in Revision, my mistake! Thanks for clarifying this.
There was no bug then (unless the OP is talking about default Revision, he didn't give a lot of info).

Thanks for checking the Biomod requirement. Unfortunately I don't have a save before she found me infiltrating in UNATCO base, which I believe is the reason why I can't say a word to her, when I approach her. I wish I could use the killphrase, but I just can't, it seems that's only posible in the 'meeting' cutscene.

So, would I be incorrect in presuming that the only things that count to the porcentage of completion (that trophy thing in the interface) in Galaxy, are the things listed in the .pdf file of Revision? Or it's adjusted, depending on what you decided to use?

The Challenges are a Biomod thing and are only available when playing Revision in Biomod mode.

The things in the .pdf file are the Galaxy achievements, which are copies of the Steam achievements. Those are unique to Revision and what I made and yes, they are the only things that count to the completion percentage in Galaxy. The challenges were made years ago to fill in for achievements I'm guessing.

Thanks, I'll not worry about Biomod Non-lethal achievement then! =)
I got tired of worrying about the protection of unconscious bodies.
Funny how Biomod considers that you've murdered someone if an enemy shots a barrel and toxic gas kills the sleeping creature, but if an enemy shots another and he/she/it dies, it's ok.
I like challenges, but things like this are unfair, imo.

Yeah I consider taking them out the hard part, when that's done I don't really care if you drown them afterwards or blow them up.

By the way, using a cheat will disable being able to get achievements for that playthrough (unless you reload to before you cheated).