Picked this up after asking for recommendations with a similar Setting as Ever17, thanks to /u/8ccc9's recommendation. It's a OELVN and probably the only one I've read aside from Katawa Shoujo. I finished it in two sessions of ~5 hours.
It's a short VN divided into three parts, with the first serving as a common route after which you branch into one of the four routes. The first route has a bit of exploration to it and one could even go so far and call it "light gameplay" in a text-adventure sense. In the proper routes choices matter and you have to put in some thought to get to the endings. It isn't always immediately obvious what kind of effect your choice had, so it can seem quite counterintuitive until you figure out the system and general thought behind these choices. That's also true for the exploration part in the beginning where you might feel stuck otherwise. Choices in general, no actual spoiler I thought this system was rather clever and it was pretty fun to figure out, it made finding the way to progress pretty rewarding. Of course it's not as fun if you get stuck, so I also made use of the hint guide which helps you pretty clearly without spoilers and choice-by-choice walkthrough I found in a review.
There is no romance involved, Adrift is a pure mystery. It's story and setting are solid and interesting, and so was piecing it together with information you learned route-by-route. The characters may be somewhat extreme to the point where they can get unbelievable or annyoing, but it's not a major problem.
Visually it is of course somewhat sub-par as an independant amateur title, but the visuals, especially the backgrounds, still have their own character and fulfill their purpose well. The music wasn't remarkable as well but didn't strike me as bad either. Some sound effects were annoying. The whole VN is a bit rough around the edges, but that's to be expected.
For an example of the visuals and a look at the nice intro sequence which describes the setting pretty well, I recommend a look at the review I posted above. I couldn't snap pictures on my own for some reason.
All in all I gave it 7/10 points, grouping it with a number of professional VNs with that rating.