Syd has written a thorough review of this game so I'll just share my impressions. Overall, I found this game to be a disappointment. Not a bad game but not an enjoyable one either.
I really tired of the timed sequences (as did Syd) and I found the cursor clumsy when trying to grasp or find an object. The graphics were good overall. I found the plot to be rather boring and it barely kept my interest. If this is an example of Cryo's best, I don't find it surprising that it is in financial difficulities.
To me, this game lacked overall atmosphere that makes one want to continue playing / exploring with enthusiasm. There is no IT factor (as one reviewer wrote about Amerzone, another game with great plot and atmosphere). I have to confess that I had just finished Dark Fall before starting this Nautilus and DF is loaded with IT and atmosphere. Nautilus should have had more ambient noises going on in the background and, perhaps, more of a stalking feeling from the Robot or even the spectral Nemo. If one has to explore an abandoned submarine, one should feel more scared in doing so; I just didn't feel it.
Overall, I'd give this game a grade of C-. I'll be trading it away.