First thing, extremely terrifying atmosphere, even after I knew how the game operated the feeling uneasiness remained. Very interesting idea for a puzzle, very engaging and unique.
I managed to get the door handle once, on what I think was an accident. Because I've been unable to reproduce it despite entering what I think is the correct code, so I've been unable to experience the full game.
Despite the liking the concept for the puzzle I think there are a couple of problems in its design.
1. The signals. They vary by about 400hz, which seems like a lot but when you hear them separately it's very hard to know which one was higher or lower, I might also be partially tone-deaf(clinically) making this puzzle almost impossible to solve. I resorted to recording clips of the sound to check the frequencies in an audio program to get the right order. Still somehow couldn't get it to work even after I got what I thought was the correct code.
2. There is no hint in game to suggest the order it lowest to highest, you have to read the game page to even hope to solve it, which is not great for immersion. Maybe a small sticky note on the machine could help, or a metal sign next to it.
3. Why does the machine give me a door handle, or more importantly why would the player expect it to do so? After seeing a prompt about a missing door handle I spent good couple minutes walking looking for it to no avail, only by reading the comments I found that I need the radio puzzle to get it.
4. Rotating the dials should be possible both ways, or at least the player should be able to hold E until instead of having to spam it. This might have been done to prevent cheesing the puzzle, however based on my experience it made me feel pain each time I reconsidered the solution and wanted to try a new one.
The other thing is the monster. It's a very cool design despite being simple. No matter that I saw it like 10 times, it still made me jump and feel uneasy when it appeared. I don't think there is a way to avoid it once spawns however. Which means walking into it and trying again is the only way to get rid of it, perhaps it should despawn after a moment if the player runs away from it and isn't looking at it. Also, once it killed me through a wall, which while scary felt a bit cheap.
Next, very minor thing. Interact text is white making it hard to see with the flashlight sometimes. It could do with an outline or a shadow effect to be more readable. Also sometimes goes off the screen, I haven’t used unity so I have no idea what might be the cause for that.
Other minor thing, footsteps sounds sometimes clip the volume making an odd clicking noise. It’s, again, very minor thing, and should be easy to fix, but I’d rather bring it up rather than hope the developer will find it themselves.
Lastly, the boat used in the intro really clashes with the bit-crunched and low detail of the facility, and on one hand it highlights the ruined state of it. But on the other hand it very much feels so different I knew at a glance it was imported from outside, it did not fit the style. Maybe adding some noise to the texture or playing with the colors would make it feel less like an outsider. It’s seen for just a moment so I don’t think it’s especially high priority.
Despite being stuck with a puzzle which I knew how to solve but couldn't get right, I had fun through the atmosphere, which in my opinion is top notch for a horror game. The loud metal footsteps and the shader crunching the colors really made it feel lonesome and derelict. The music in the intro also pulled its weight in making me feel like there is no one to hear me scream. Overall, could use some work in some parts, but already excels in others.