Other comments already said the same thing, but:

Performance issues
I had so many issues on my high end gaming PC. Especially because for some reason my graphic settings would just revert back to the automatically calculated values every time I opened the game. It was using between 7.5 and 13 GB RAM. Thats insane af. Going to certain areas would load so much stuff at once, the whole game would just freeze up for a moment. I had to restart the game every time it started using resources like crazy, so something aint right.

Narrative
- lots of plot is just squished into narrated text on screen
- one of those endings where you gotta fill in the blanks and decide what to believe yourself
- plot does not frame mental health well, basically ye old mentally ill person = bad and violent murderer plot. This enforces stigma around mental illness and is frankly uncreative. You get to stuff your plot with crazy scenes and then whatever doesn't make sense is cause of delusions.

If you can run the game on ultra, it looks beautiful though and I did like the whole involvement of the camera and developing pictures. It could be an really good game if they optimised the game better and actually committed to the plot they set up.

Not a bad purchase. Not a bad experience. One of the more titles that are worth it within the Genre.

4/10 - Three words can describe this game: Walking Simulator Drama.
At best this game is a painful walking simulator with random mini games.
I was so excited to play this game, it looked so good from the trailer and I was incredibly disappointed.
As someone who does enjoy horror walking simulators and who has played some good indie horror walking simulators this game is so incredibly half-assed.

Pros:
1. Sound design is a 5/10. The "scary" music is just annoying, it sound like someone is using a handsaw on a violin and the sound of the boat engine is like nails on a chalkboard.
2. The voice acting is pretty good.
3. The graphics are nice
4. First hour or so of the game is good.

Cons:
1. Nothing scary happens for long stretches of time.
2. Next to nothing to guide you on how to progress the story other than some vague instructions.
3, You have learn Morse Code: which is hard enough but they have you read it off of a tiny piece of paper.
4. THIS GAME IS SO BUGGY: You will randomly spin like crazy and lag out of nowhere.
5. The "monster/villain" in the game very quickly goes from being a threat to being an asset.
6. Random pointless scenes that make the game feel very thrown together, desperately needs better editing.
7. You interact with almost no one outside of the game's first 15 minutes. There's 6-8 characters you never actually see, you're completely alone for 97% of this game which gets old very quickly.
8. Camera mechanic is boring and gets old fast.
9. The story telling is poorly done and makes it hard to care at all about your character.
10. You spend more time getting stuck on/running into invisible walls than there is story. The annoying navigation and the sheer amount of invisible walls is so obviously just there to extend the play time. You can't just cut through the woods you have to follow these poorly designed paths. With the constant glitching this becomes incredibly tedious.
11. NOTHING scary happens after the first hour except for a few kinda creepy scenes.
12. A lot of the important plot lines are revealed through puppet shows which was kinda cool at first but are clearly a lazy way of rushing the story along at the end.

Achievement Issues
If you're wanting to 100% complete this game, good luck. There are several broken achievements. I should technically have all of the achievements but the one for phone calls is broken and has been for years. I tried Googling solutions, checked Reddit, and other gaming websites. I spent nearly 2 hours trying everything people suggested to get the achievement to work. The only thing I didn't try was completely replaying the game because even that isn't guaranteed to work and I'm not torturing myself with replaying this game.

Despite a great premise "Martha is Dead" is wildly unfocused, calling it a horror game is generous. The trailer is the best part of the game.