4.5/5 - Great

I absolutely loved it, an excellent game and a noticeable improvement over the original. The level design was full of variety and challenge, the new pirate abilities were a load of fun to play with, the writing was very entertaining, the music was phenomenal and exploration was a blast. I could bring critique to the odd backgrounds and effects that often use auto-downscaled high-def images and look kinda bad compared to the gorgeous pixel art, as well as various times the game was rather cryptic, but I overall really enjoyed it. I thought it would be fun to rank every island, so here is my ranking:

6. Spiderweb Island: this is by a landslide the game’s weakest point, where I was barely even having fun for a lot of it. The starting area is absolutely full of annoying enemies that spawn on top of you, it's impossible to walk or even jump for 2 seconds before a zombie or a ghost just appear in your position and damages you, and fighting then isn't interesting nor is there much platforming here so this part is a bore. The Rotty carrying minigame was alright but far too much of it was waiting for things to move and I felt it overstayed its welcome. And the dungeon, while having some excellent level design, was the most confusing of them all, with a lot of places I struggled to navigate even with a map. At least I like the boss. Absolutely a mess of a level.

5. Saliva Island: yeah Spiderweb was the only level I didn't like, Saliva is a lot of fun, just not as great as the rest of the game. The earlier parts are great, with some fun platforming and enemies and some cool puzzles, although it can also be a tad confusing, and some of the enemies shoot projectiles with too little warning. The dungeon was great and used the pistol for lots of cool puzzles. Some flaws but a very fun island.

4. Scuttle Town: I'm only counting it because of the dungeon at the end. Throughout the game, there are a few neat things here, like the areas from previous games you can explore on your way to the palace and the sewer area, but at the end the final dungeon taking place inside the palace was one of the game’s highest points for me, bringing a genuinely awesome final challenge that tested all your platforming skills and a very fun final boss. It only falls here due to lacking some of the substance of other islands as a consequence of technically not being one.

3. Mud Bog Island: a great level - it's brought down by the early parts that I feel get too enemy spammy, with parts where there's basically no escaping damage, but as soon as you enter the cave of lost souls it jumps way up - the cave itself is full of some of the game’s most interesting writing alongside great level design, while the dungeon within was nothing short of excellent with lots of memorable moments and good challenge. The boss also felt a bit messy but I still loved the place.

2. Frostbite Island - going from slippery ice slides to aerial flying and swinging, to a dungeon full of cool gizmos and engaging level design, this entire area was a blast. I could describe everything I loved about it but assuming you played the game you'd already know, not much at fault to point out here. It just barely loses the top spot to…

1. Tan Line Island - this place has it all. The entrance area has fun combat sections, lots of cool secrets and uses of your abilities, and one of my favorite puzzles, the mod part’s stealth sequence was very unique and fun, the platforming within the dungeon was among the game’s alongside a very fun to explore layout, and the boss was a lot of fun and very funny too. This was the point I was really starting to love the game.

An excellent game, and my personal favorite in the series. Pirate's Curse admittedly plays a lot differently from the "standard" Shantae style, but I always loved how the abilities mesh together. The music is incredible as always, and the visuals combine the pixel art style of Risky's Revenge with more anime-esque character portraits. The one thing I don't like is that the pacing can grind to a halt at times for the sake of seemingly random diversions (Rottytops and the Tanline Temple segment come to mind).

Where it Shines:
Music - 8/10
Humour - 6/10
Pixel Art - 7/10

The Good:
This game as a metroidvania is quite well done. It's nothing special, but there are a lot of things to collect and unlock without being too much, and the platforming and level design is very good. That combined with the art and music make for mostly a pleasant play through.

The Bad:
I have to comment on the stereotypical use of culture for Shantae, and the hyper sexualization that often accompanies female protagonists of this nature. I know Shantae, as an IP is quite old, so at the time with these games I was just sort of happy to see any brown skinned person in a game.
I think this game in particular doesn't lean too hard into appropriation, but it's still there as an undertone.
That aside, it's also just sort of a medioce experience - I think there's far better metroidvania's out there, though maybe not as bright and colorful as this one.

Summary:
You're not missing anything by skipping this, but it's not a horrible game by any means.

****note on my ratings:
half ⭐: hot trash garbage
⭐: below average, needs work
⭐⭐: average
⭐⭐⭐: pretty good
⭐⭐⭐⭐: excellent
⭐⭐⭐⭐⭐: all time favourite
half star ratings between those mean it's slightly better or worse than stated in this list.
*

Enjoyable gameplay, varied locations, entertaining characters, well animated, and has a good soundtrack.

There are metroidvania elements, where you will need to obtain certain equipment that can be used to interact with the environment if you want all the collectibles and optional battles, instead of one connected world you travel to six different islands that each have their own themes to them. There is a more brisk pace to the areas with them not overstaying their welcome in your initial run through them.

While the game has the islands as separate locations and you are initially moving from area to area and interacting with new elements of the game fairly quickly, you will need to backtrack to those earlier sections if you want or need to go back to previously inaccessible areas and run through the same enemies that both stop being much of a threat but that also might now be showing up with a higher spawn rate. The limited amount of branching paths and the fairly obvious nature of the hidden areas also means those that like exploring or uncovering secrets won't have much to find in this area. Going back later in the game to collect hearts and dark magic just isn't that interesting. The new gear you find allowing you to get past a block or a jump you couldn't get through before. The NPCs you meet are entertaining but lack much variety in dialogue when you come back. Later on some of the equipment you find can make traveling through those areas very fast but it would have been better if going back was more fun in itself.

Very good action platformer, that would likely have been even better if it was linear in nature and if the time creating those side initially inaccessible areas were used for more content as you go or to touch up existing spaces.