This is really good! The artwork is very nice, love that old sea chart style, the music is fitting, and especially the tutorial is very very well done! I love the gameplay a lot too, this reminds me of the old mobile game where you divert flights to land (I've forgotten what the name is though) and it is very enjoyable. Speaking of mobile games, this would feel quite nice to be played there too!
The few and far between criticisms would be the difficulty is rising too slowly for me, probably I am expecting the level of difficulty to start at what currently the game does around 600-1000 points. It makes the first part of the game (which is not chaotic enough) quite slow and boring at times. Also, it would be nice if the randomiser didn't generate the same colour of ships 5 times in a row, probably some sort of pseudo randomiser would be nice.
Anyway, this is a very good game and I like it very much! Well done!
P.S. It's always nice to see a custom and themed pause menu so huge kudos for that