About THAT one obviously bad part in Alien Romulus [SPOILERS]

Could have been done just with a well directed animatronic coupled with some basic CGI to enrich some textures and details.
That's exactly what they did. A full head animatronic of Ian Holm's likeness was built.
People who claimed to have been at a preview screening say the effect was fully practical, but that it was also a little distracting because it looked like a "muppet" (Their words, not mine.)
So in the intervening time between previews and release, they have used AI and CGI to apparently make the eyes and lip sync movement smoother for a better effect.
I agree it looks jarring in the film and I would personally like to see the raw practical shots to see how it looked beforehand.
- I could mostly tell which shots were the puppet and which were CG, and the combined effect was jarring. A few shots looked fantastic, but they were the exceptions. If this were a short scene or cameo, it would have been fine. But he turns into a major character, and it's a major failing of the director to not have the effects nailed down when it's so central to the film.
  There's also no reason at all that it had to be Ian Holm, other than misguided continuity porn. Him being the same model as Ash has zero bearing whatsoever on either this story or the lore as a whole.
  
  There’s also no reason at all that it had to be Ian Holm, other than misguided continuity porn. Him being the same model as Ash has zero bearing whatsoever on either this story or the lore as a whole.
  I don't think this is true. It connects what's happening on Romulus/Remus station with the Nostromo and heavily implies that Ash was always on the Nostromo because it was always intended to rendezvous with the planet/moon (LV-426) and that the Ash model was in some way ideal for or dedicated to the xeno/goo research program.
  I can't recall the exact details, but from Rook's info-dump we know he is aware of the events in Prometheus to some extent, in which case it makes sense that WY were aware of something valuable being out there. It's explicit in Alien that Ash was added to the crew last minute and so it's clearly implied that his ulterior motives originated from before the launch of the Nostromo. That Rook is the same model adds weight to this.
  It also kinda widens the range of things happening simultaneously in the alien universe in a relatively organic fashion. David (prometheus) could still be out there or his ship in some way, and Rain is now out there, and they both have the black-goo, plus the planet in Engineer planet in Covenant, the planet in Prometheus, the surviving Queen from Aliens (?) and maybe the ship from LV-426 survives the nuclear blast to some extent ... all within decent time-proximity that some creative license could easily leverage.
  
  Totally agree. The parts where the model was shadowed looked okay but then BOOM cg shots where the mouth kinda floats on the head.
  And ultimately you’re right! …but I’m still conflicted. It did not need to be Ash. That was just BS fan service… BUT having the same android does cement a through line, a type of connective tissue that communicates how weyland-yutani have had a constant eye on this species the whole time. Basically visual shorthand to say that since Alien 1 the corp has had eyeballs.
- Yea interesting. I’d bet the animatronic also landed somewhere in the uncanny valley. Which is why I feel like the problem is that they wanted to put a spot light on the character. The better option is to cleverly obscure it just enough. Broken mechanics/manerisms as I suggested would be one way … shadows another. Full on close ups were not the right choice. In the end it was probably a misstep by a director not experienced enough with that sort of effect.
- To be honest, it looks about as good / bad as all the other deepfake face swaps I've seen, in and outside of commercial media. It's just nowhere as good & convincing as some people would claim it to be in those various "AI" hysteria articles.

Reminded me of Space Babies.
Interesting that you pick this as the worst part because what tipped me over the edge was:

I was cutting it some slack on the long list of references to early films as I was liking what they were doing but that made me go "oh Fuck right off".
- Ha. I saw it coming I guess, and I figured why not have some fun. Apart from the line, the whole scene was pitched as very triumphant, so I’d say I didn’t like the whole scene that much and the particular bit was just part of it.

I agree, but maybe not that it's a love it or hate it film. I liked it. I really enjoyed the space shots, but the CGI of Ash was horrible and brought down the movie.
- Yea I enjoyed it too. Just wish it was better, in part because it’s got good foundations.

I noticed this, but it didn't bother me that much. Other than the deepfaked lipsyncing failing 99% of the time, I wouldn't have noticed that anything was amiss. I didn't even think about the voice being AI, but that makes sense to me.
- Yea it's definitely the sort of thing you can ignore I suppose, we're kinda in that era now with CGI, which is fine.
  What irked me is that when seeing it, I immediately thought everything in my rant. Presuming I know enough about how films are made (perhaps a big if), it was like watching an athlete needlessly trip over themselves ... where to me it was obviously a mismanaged series of shots that could have been done much better.

I loved it. Andy was scary as fuck. I like that it focuses on the synths so much.
But holy shit what the fuck was with the Ash synth!? lol I can’t imagine it looked worse as a practical affect because it was shhhiiiitttttt
- Yea, let’s get the “puppet cut”!
  It was clearly a fuck up, and the film is almost lucky to have been so good in almost every other aspect that we can forgive the ash synth CGI.
  It would be really cool if someone just put the work in to clean it up for a blue ray release or something, just for the fans and the franchise, which is going on 45 yrs now, as old as Star Wars.