Pulling my hair out over this one, but I was wondering if through extensive play or understanding of the code anyone knows the right conditions to trigger the Dektora romance endings (either skipping town or being seat buddies in the moonbus). I thought I'd finally got an optimal playthrough - Dektora as the main replicant of Act III, being consistently nice to her, careful not to befriend Lucy and trigger that romance option etc. - but however I play Act IV, I end up getting the Act V call from Steele or Clovis, depending on how many human NPCs and / or LPD grunts I choose to inhume during Act IV, whether I turn myself in with Guzza's evidence or not, etc. Have tried many permutations, but the balance of favour seems to go straight from Steele to Clovis and vice versa, with not a peep from Dektora.

Granted, it was a relationship out of the blue (though plausible assuming replicants really do have to seize their moments for joy), but it would be nice to have a romance option on the sympathiser / replicant path, and the Lucy option just feels too squicky. Knowing that both Lucy and McCoy might technically be both three-year-olds or therabouts doesn't help much.

In the game proper it is possible to romance Dektora only if she's a Replicant and as far as I recall:

(spoilers follow)
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It's best if she's the last Replicant you encounter on Act 3, meaning, she's the one who calls the cops on McCoy, and later McCoy has to hunt with Steele. I which case you need to catch up to her, and let her go, before Steele catches on with McCoy.

I've had a similar discussion on the ScummVM discord a few months ago. Since I can't remember the specifics of Dektora's AI behavior, I'm quoting myself from that discussion.

"The thing is that Dektora has a few conditions that may lower her friendliness towards McCoy, a few of them are affected by the dialogue in her dressing room, or stuff like McCoy revisiting her multiple times in her dressing room, or her knowing that McCoy is a Blade Runner in advance"... or clicking on the vase with the flowers (under some conditions)..."

So, visit her only once, better not to touch the flowers (...) and, of course, you should definitely warn her about Steele.

There's also a way to track how friendly she is towards McCoy and how McCoy's actions and questions affect that, but you'll have to use the ScummVM debug console for that and it will break the immersion, so I'd only recommend this option, if you are really curious to see how it works.

What I do recommend is using a recent ScummVM build with the game; current stable is 2.1.2, and in a few weeks we're releasing 2.3!. This has the benefit that:
- We keep fixing any bugs reported to us
- We are tweaking performance and making optimizations to AI behavior and game scripts.
- The debug console (should you decide to use it) has a known issue with the ScummVM build that the GOG Blade Runner release shipped originally with.

Thank you so much for getting back to me so quickly (not to mention for having restored this game - it was a rare bright moment during lockdown to see it not only available again but given such TLC). I may well have sabotaged myself with the flowers, according to your info. Looks like it's back to my start of act 3 autosave ... Tempting to use the debug console, but I'll see how I get on without it first. x

Confirmed (spoiler alert)
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It was indeed the flowers all along. Whether or not I touched a bunch of flowers was the difference between Steele thinking me a decent guy and wanting to put a bullet through my head (I got through Act IV without having to kill a single human). NPC jealousy is a weird thing indeed ...

Double Confirmed

Wow. Even taking Guzza's briefcase to the cop shop and getting cleared by Bryant made no difference: Steele still shot the poor doggie and Dektora made the sympathetic phonecall. I shouldn't be surprised at that, as there have been many times I've tried to play mostly ruthless while keeping my word not to hurt Lucy, and ended up having to go on the run with her. Evidently, getting a replicant (or even human Lucy) infatuated with McCoy is one of the unforgivable curses in Steele's policing manual.