Sure! :D I can try to offer some feedback about the two. :) You did well though so this is just thoughts which may help with doing better.
I'm not too sure for Concept and Originality - it's a tough category and the contest didn't leave many options open, so most people lost points in that category due to how it's hard to be original. The gist is basically "How unique can you make it, and how much depth can you put into the lore of it?". Judges are human though so I'm sure some errors were made on a few submissions for it as it's a vague category anyway. In this case your build was one of those which went with the fairly straightforward "it's a pirate cove city with ships", so it lost more than many may have, while something like pirate paradox threw out a creative idea of a pirate opening a treasure chest to find a pirate opening a treasure chest- and so on and so forth. Creativity, basically. That's that category. :)
Technique and execution is easier to assess though, and in many ways there were aspects of the build which could definitely be improved, such as the smaller ships with very stiff masts, and even the bigger ones had stiff masts too. There's a lot of flexibility with billowing in the wind for ship masts and it's usually not so "tidy", so that tends to help. Besides that, the point of far more note were the structures in the build, most of which were of pretty simple designs. If you look around the structures of other finalists' submissions you might get some ideas about how the detail-level, palette choices/colouring and the overall shaping could've been improved upon. It's complex to summarise though so it can help to take inspiration and think it over that way. :) The terrain was also quite simple, and the trees used are default trees, while most submissions used complex, detailed custom trees they'd made, which tends to make it feel a lot more alive. There are other ways it could be improved too, but- I think those are the more obvious ones.
Overall, I do like your build though, so just to make completely sure, don't let any of this get you down. :D These are just points with extra room for improvement- and pursuing such improvement offers a lot of opportunity for the future, so learning from your mistakes is great and I'm glad you asked. :)