I'm a big fan of small-but-mighty builds. Huge MOCs are amazing, but with smaller MOCs every part counts -- and I think you've proved that here. I pulled up the original set and my first thought was to smile. I think you've done a grand job paying homage to the OG set, while also bringing a modern aesthetic to it.
The trick with these sets is balancing simplicity with design. Overall, I think you've hit that balance well. Excellent shaping with the palm tree - it brings a perfect pop of color.
I have three suggestions/critiques to ponder:
1) I think building out the angled water and pocket of land is the right call and you've layered it well. I noticed the water isn't quite symmetrical. I like the shape, but the emptiness of the smooth part of the plate feels like it is missing something. Was there a reason you didn't use the same wedge plate as on the other side?
2) Excellent shaping with the palm tree. It brings a perfect pop of color. If you wanted to continue the the diagonal visual (started by the palm tree), make the 3-point leaves the same green shade as the palm tree. Your eye already catches the angle of the leaves and this will bring attention across the build. If you had a red parrot, putting that on the palm would also bring the eye back up that diagonal line, highlighting the red carriage for the cannon.
3) As for the wall, you've done a great job representing the original single (and stickered) wall. The clips on the inside to hang weaponry is an excellent upgrade. From the outside, however, it seems to lack the same level of detail. Interspersing stacked plates (instead of bricks) might help, especially if you did a square plate, round plate, square plate sandwich. It would give that iconic weathered look of the original. I've included a pic as an example.
Overall, great clean build. Wish you all the best!