The tutorial text could use better layout so that it doesn't jump up when the "press button to continue" prompt pops up. It's really cool that you were able to add a tutorial.
It'd also be nice to have text not reflow in the middle of showing more text.
The redaction tape felt a little low when I first started. I kept starting the redaction too high so I had to go over it twice. After a little bit, I adapted, but it'd probably help to put a virtual cursor with the height of the redaction to make it easier.
I experimented a bit more and it seems to mostly be a case of the shader warping the screen. If you did some reprojecting of the mouse cursor that might also help. (If you click the bottom point of a capital M it places the tape differently when it's on the top of the screen vs the bottom in the first screen after the tutorial.)
One thing I thought about while I was redacting is whether I should mark wide enough height wise to mask the bottom of a 'g' even when there wasn't one just to make it harder to decipher when someone reads it back. Not sure if you're detection is that strict, but something to think about.
The music fits pretty well with the feeling of the game. The timer sound was a good touch and it did make me speed up the last few to make it in time.
The shader does look a little wonky at certain resolutions like when it's embedded and not fullscreen (I'm using a 1440p screen). It looks good when fullscreen.
I like the detail on the documents and how they're written. It's good enough that I was immersed in the world.
Overall I like the direction you took the prompt in and executed it well. I'd play more if there was more.