Not only was it a pretty pointless and lazy twist...
Pointless? That's being too harsh. Ed needs to transition from one of the protagonists to the antagonist and the player needs to be motivated to want to stop him.
For example Ed acted surprised at the power outage in the beginning, even so he was the guy who caused it.
The commentary explains that Ed didn't know that a Resonance reaction would cause an EMP pulse that caused the black-out. An answer that needs to be given in the commentary isn't a very good one, though.
Later on Ed lets Anna lock herself in the vault and shoots her while the vault is still looked. Kind of stupid given that the vault is supposed to self destruct when tempered with. He then of course opens up the vault by shooting the control panel... yeah. And when the situation ends, Ed himself is locked up in the vault. How exactly did he get out of that?
I think Ed is supposed to be desperate and irrational; he shoots Anna regardless of what she (i.e. the player) decides to do with the vault.
I agree that that sequence (especially shooting the panel to open the door) was kind of stupid, though. It really looks bad in comparison to the rest of the game.
On top of that of course the twist completely ruins player agency in more then a few ways...
Ed leaving the player's control, you mean? I think that's a tough question. Ed beginning to act without player input is necessary for the story. Do you think this kind of story, where a player character has motivation that is hidden from the player and eventually acts on it without player input can't work?
...because it's the only women character that get killed the whole thing feels very much like "Women in Refrigerators" kind of trope.
I think that's a little unfair. She's there to get killed and her death is supposed to provide motivation, but she gets nearly all the characterization in the game and it's the loss of that character, not just a woman being murdered, that is supposed to shock the player. Her murder is also not the only motivation for the last act; Ed is going to set off another explosion.
Large parts of the first half of the game are wasted on Anna's memory and family, all of which is completely irrelevant in the end.
The story had really run its course when Anna gains final access to the vault and sees the message Javier left for her. Where else is it going to go? And I say the way it's cut off is supposed to emphasis Anna's death. It doesn't
matter any more because Anna is dead.
Furthermore the main antagonists in the game never gets any screen time whatsoever, you meet them once and that's it, you never see them again and you never explore their backgrounds in any serious way.
Amul and Reno do feel like an appendix, and it is annoying how much they drive the events of the last act despite this. I think the developer (his name is Vince) intended to bring them back in another game. He needed a lot of help from Wadjet Eye Games to get this one out, so who knows if that'll ever happen. Sequel-baiting is also a pretty annoying thing to do.
All the interesting stuff is simply not part of the game, but just some computer behind a door that you aren't allowed to touch.
You're saying the secret DNA database is the only interesting part? I wouldn't agree because it's so poorly developed and goes nowhere, like Amul and Reno.
I derived a lot of interest from Ed's misguided motivations and just the fact that Bennett and Ray are fun characters to pilot around.