I think the Dissociative Identity Disorder [DID] theory is a valid interpretation of the story and one the author intended as a possibility. I also think the origin story for Eve as a twin is kind of garbage and highly implausible, however implausible and impossible are very different.
That said I've given it a, probably unreasonable, amount of thought and I think Eve is a twin and not a personality. What follows is a stupidly long post of somewhat raw transcripts on various topics and my interpretation as what I think is the strongest evidence that Eve is a real person, so grab something to eat if you are heading in...
MURDER WEAPON - 2 MIRRORS
- Hannah agrees to discuss the argument and is hesitent to get into the details. (25/06/94, D210)
- Hannah states Simon gave her the present and states 'I guess I didn't like the present' (25/06/94, D211)
- Hannah confirms the present was a mirror. (25/06/94, D212)
- Eve responds to a detective query about the mirror. States she thinks it is upstairs. (27/06/94, D350)
- Hannah picks up the mirror in an evidence bag confirms Simon made it himself as a special one off. Asks where they found it. (30/06/94, D417)
- Hannah denies silverleaf and states he silvers them properly. (30/06/94, D418)
- Hannah responds to a detective query about 'being on his clothes.' States that makes sense as he made it by hand, brushing the silver onto the glass. (30/06/94, D419)
- Hannah puts the mirror down, touches her throat and asks 'In his throat? How?' (30/06/94, D420)
- Eve states Hannah was wearing Eve's wig, pretending to be her. Stated Simon wanted to be with her. (03/07/94, D767)
- Eve states Simon pulled out 'another mirror' just like the one he'd given Hannah earlier. 'That unique present.' (03/07/94, D767)
- Eve states Hannah went crazy and smashed the mirror. (03/07/94, D767)
- Eve states Simon hit her so she grabbed a piece of the mirror and swung it around and cut his throat clean open. (03/07/94, D767)
- Eve states they bagged up the broken mirror and her clothes. 'They're gone.' (03/07/94, D768)
- Eve states they, the police, have no murder weapon. (03/07/94, D771)
The video D767.avi is the most important video of all the videos recorded. It states, in no uncertain terms, that Hannah dressed up as Eve, convinced Simon she was Eve, Simon admitted he wanted to be with Eve and gave her (Hannah dressed as Eve) a duplicate of her unique mirror. This is the reason Hannah lost it and killed Simon. It is an absolutely vital scene to explain everything else that happened.
The fact that there are 2 mirrors is one of the strongest arguments that Eve was a twin. Simon was completely convinced Eve was another person. Eve is confident in the final moments that the police have no murder weapon because they have Hannah's unbroken mirror, not the murder weapon. There being 2 mirrors is an absolutely vital component to the story. One mirror being broken and being the murder weapon, and one being intact and in the police's possession is vital to the closing scene.
FINGERPRINTS
- Hannah agrees to having her fingerprints taken. States she burnt her hand on the oven once. (25/06/94, D230)
- Hannah responds to a detective query about fingerprints. (30/06/94, D403)
- Hannah states no one has been in in the last few weeks besides a plumber. (30/06/94, D404)
- Hannah responds to a detective query about the bedroom. (30/06/94, D405)
- Hannah discusses her dusting regiment. Says she dusts weekly, maybe every few weeks. (30/06/94, D406)
- Hannah responds to a detective query that appears to be the last time she dusted or cleaned. A week or so ago. (30/06/94, D407)
- Hannah states she 'would have cleaned them too' and she changed the sheets too. Asks 'were the fingerprints in all those places?' (30/06/94, D408)
- Hannah suggests the possibility they are her parents fingerprints. (30/06/94, D409)
- Hannah responds to a detective query offering her cup saying 'run your fingerprints' and saying 'they'll match.' (02/07/94, D607)
Based on the line of questioning from the detectives and the responses to those questions it is a reasonable assumption that the police found an unaccountable set of fingerprints in the bedroom. Three total fingerprints. Simon, Hannah, and Unknown. The unknown fingerprints were Eve's.
PREGNANCY
- Hannah states she got pregnant with Simon's baby. (25/06/94, D218)
- Eve corroborates the pregnancy. (03/07/94, D744)
- Eve states she tried multiple times to get pregnant and it didn't happen. (03/07/94, D745)
This makes absolutely no sense from the DID perspective. If Hannah and Eve are the same person, when Hannah got pregnant Eve then went and had sex multiple times to also get pregnant so they could keep up their swapping lifestyle. Eve is not able to get pregnant. If they occupied the same body, she would have had sex, taken a pregnancy test, and it would have been positive. The pregnancy and miscarriage plot line does not work with the DID theory.
HAIRBRUSH
- Eve states they took Hannah's virginity using a hairbrush. (03/07/94, D743)
If Hannah and Eve occupy the same body it is kind of difficult for her to lose her virginity twice.
TICKET
- Eve confirms she is in the photo of the speeding ticket back in February. (01/07/94, D526)
- Eve states she popped out to get something and did not mark it on her timesheet. (01/07/94, D527)
GUITAR
- Hannah denies Simon plays guitar and was not very musical. (30/06/94, D445)
- Hannah confirms that it is her guitar. Video cuts off early for the first time. (30/06/94, D446)
- Eve agrees to play guitar and sings a song. (01/07/94, D536)
I think the ticket and the guitar are the strongest evidence that the police knew something was up and were working out what exactly. They bring up the discrepancy with Hannah being in two places at once by receiving a speeding ticket and also being at work.
The guitar is also very important. If you watch the final videos for Day 4 they start questioning Hannah about a guitar and the video abruptly ends. Every day prior it is clear we have the entire video. It starts with Eve or Hannah just arriving and getting a drink, and ends with her getting up and leaving. On day 4 the video just end. Maybe this has to do with the missing volume in the DB Checker.
This is purely my speculation but I think if the video were to keep going it would be clear that Hannah has no idea how to play a guitar. This would be in stark contrast to Eve picking up the guitar the following day and singing a ballad. Maybe the author took it out because it made it too obvious? Who knows, but the video absolutely cuts out early. Go watch it for yourself.
GLASGOW
- Eve details her trip to Glasgow. (27/06/94, D309-D312)
- Eve maps out her trip to Glasgow. (27/06/94, D333)
- Hannah reiterates she was in Glasgow and asks if they spoke with the hospital. (02/07/94, D603)
- Detective appears to accuse Hannah of sounding rehearsed. (02/07/94, D604)
- Detective appears to ask about twins. (02/07/94, D605)
- Hannah angrily ends the interrogation early and leaves. (02/07/94, D609)
- Eve reiterates the trip to Glasgow. (03/07/94, D764)
When Hannah challenges the detective about her alibi of being in Glasgow when the murder happened their response does not appear to be that they did not check. This was my first interpretation. Instead the detective responds by accusing her of sounding rehearsed, and asking about a twin. This line of questioning says to me that the detective did confirm Glasgow, and the speeding ticket and the guitar are part of trying to figure out if she could be in two places at once and increasingly finding evidence of things not adding up. If any character is deserving of brilliant mastermind it is the detective's ability to deduce something as radical as an undocumented twin.
BRUISE
- The first time we see Eve she has no bruise. (18/06/94, D101)
- The first time we see Hannah she has the bruise. (25/06/94, D201)
- Hannah states she got the bruise from slipping and slamming her face into a cupboard (25/06/94, D203)
- The next time we see Eve the bruise is missing again, 2 days layer. (27/06/94, D301)
- Eve touches the wrong side of her face when asked about the bruise. (27/06/94, D304)
- The next time we see Hannah, 13 days after the murder, the bruise is gone. (30/06/94, D401)
- Eve states the origin of the bruise is when she hit Hannah. (03/07/94, D763)
This has been discussed to death, but in conjunction with all the other evidence is important. Yes, if it is DID then there are plausible explanations for the bruise coming and going, but that does not change the fact that it comes and goes.
TATTOO
- The first time we see Hannah she has no tattoo. (25/06/94, D201)
- The next time we see Hannah she still has no tattoo. (30/06/94, D401)
- Eve spills coffee on herself. (01/07/94, D503)
- Revealing a tattoo of an apple and a snake she got to 'express her individuality.' (01/07/94, D505)
- Eve states she got it about 8 years back as a present to herself. (01/07/94, D506)
- Eve reiterates she got the tattoo nearly 10 years prior. (03/07/94, D752)
Same as the bruise. Too important to ignore.
..phew...
Feels nice to get that all out of my brain and if you stuck around this long then a huge high five from me. A few closing thoughts. I think the fact that the game NEVER mentions or hints at DID, MPD, split personalities or mental sickness is ultimately the point of the game. I think it was fully Sam Barlow's intention that people will see a woman in this position and naturally gravitate to "she is crazy, obviously". It didn't need to be said because we will do it automatically by constructing narrative and reading into subtext that doesn't necessarily exist.
Instead he spent all his time and effort constructing a crazy but plausible alternative possibility and completely lays it at the players feet in full detail, and still, with absolutely no explicit evidence we will still argue "yep, she is crazy, clearly." Call it an art game or whatever bullshit you want, but this is my interpretation of the narrative and what I believe was the fully intentional critique to how we view women who commit violent crimes in the heat of passion.
Hannah Smith caught her husband cheating on her with her twin sister, felt absolutely betrayed by the only 2 people who matter the most in her life and lost it. End of story.