Let me start by saying this game is amazing in many ways and the attention to details show. But it is also lacking in many others and for that reason, as it is now I wouldn't recommend it but also wouldn't not recommend it.
My main gripes with the game is the lack of clarity with the players goals. By exploring the ship and collecting the many books the player figure out the main goal, leave the ship. The problem arises from the smaller steps required to do so, for example (SPOILER AHEAD: after restoring the power I didn't found anything telling what I need to do to place the transformers back online.)
Another problem I had was with the clearance system, after getting the captain ID I got a message saying that I couldn't used because it would reduce my clearence however I still couldn't enter any of the pods because my clearence was't high enough. I guess that was a bug, because surely I should have, otherwise if not even the captain could use the pods who could leave the ship then?
These were my main gripes with the game. I still had plenty of fun exploring the ship and seeing the multiple rooms the crew had. As others have mentioned the models and the textures were very well done. As for me, I didn't experience any type of lag despite using a computer from 2014, so I guess the code was also very slick, which is always a plus.
The secret story of spacetravel has a lot of potential and hopefully in the future that potential will be realized, I have fun exploring but unfortunately there isn't much else to do where I think it should have that is why my review is neutral.
I find it quite fun to play around with the notes and wrote songs, but I think the music box design need some tinkering. The mod work by addind a disk and then going to 'Music Player' and writing the notes you wanna it to play, the problem is there is a lack of intuitiveness on the GUI, the music player has 4 'Sets' field which I assumed were different tracks but it seems like they overlay each other when playing, then the notes itself are in a different tab called 'Guide', which makes writing a song a back and forth process of changing tabs to check which notes are which and if you don't save what you wrote disappear but saving also close the formspec which can be annoying.
My suggestion would be for the notes to not listed at the side of the sets rather than on another tab so it's easier to write songs, the same may be true with gain but I haven't checked how that works, also it would be good to mention inside the formspec that you have to separate the notes with space since most people would download the mod without reading it here.
But even as it is, a person not literated in music theory like myself found it incredible easy to write songs and the idea of writing disks and exchanging among other players is quite and interesting one that I haven't seen before. I mostly kept it to the notes, but there is quite a few options to change pitch, fade and gain making the music editor quite a powerful one. I fully recoment the mod!
The backrooms is an large area where things that clip out of reality end up. It is so vast that is mostly empty, so far the game have deliver on that premise and I don't mean it in a cynical way. The levels feels disorienting and that coupled with the procedural feeling of the rooms give a strange sense of uncanny, uneasy familiarity which I believe was the original goal from the backrooms.
Now the bad, I see two problems so far. One is the lack of sound, ambience and noise are paramount in horror games to create the atmosphere, so far we get none from the backrooms game which I feel diminush the effect. The other problem is the scale, the room is too big which give the impression the player is a hobbit, I wrote a quick mod to change the player eye_height to '2.6' and the visual_size to '1.5' and I believe that gave a much more proper sense of scale. I would advise the developers to play around with that properties as I feel like the original Minetest values don't quite fit with this game.
Personaly I don't like the idea of taking pictures from the diferent places and would love if the devs expand on that idea some. Overall the experience matched my expectations for the backrooms.
Edit: Indeed there is sound, it was the humming of the fluorescent lights but it is a lot fainter than the player steps so it can be hard to notice without headphones.