I'm sorry, but I honestly disagree with a lot of this review. Before I go on, I should say that I've only made it to the third world, but I'd say I've played about 20 of the games stages, from memory, which all have multiple areas, and several are very long.
The game is simply a children's game, or a beginner's platformer, at the very best.
The stages, so far, have been incredibly simple. Essentially, each area has a few branching paths, and in the end, they all lead to a door, and you progress to the next area. Exploration is literally directing Starfy over to the end of a path, picking up the couple of star gems, items that refill your health and can be spent to buy things, and then heading back and going the other way. Three times in a world (Worlds, I believe, have 6 stages and 3 bonus stages, as well as a boss fight at the end), you'll find an extra doorway that you can go and play one of a few mini-games in, including a brief race, or a "find the item," type of challenge. When you win, you unlock the bonus stages. Each bonus stage, IIRC, contains an extra piece of a costume Chessa describes above, for dressing Starfy and Starly.
What's unfortunate is that, aside from it's cutesy atmosphere, and doll-like character designs, which all look great, the rest of the game falls flat. When I first learned Starfy could wear costumes and accessories, I thought you could "dress" him, and then the sprite on-screen would resemble the changes. Unfortunately, that's not true, and all those bonus stage costumes, as well as the ones you buy with star gems, are purely for show on the pause menu. Aside from picking out the way your CG Starfy is dressed, you can unlock brief scenes related to the themes, but it's purely a distraction from gameplay, and likely wouldn't amuse the platforming enthusiast one bit. Don't expect anything on the level of a Zelda game from the exploration, as this game's exploration is more akin to a Genesis Sonic game: There's multiple paths in each stage, and a few gems on these paths, but ultimately, you're going to the same place.
The platforming and combat, essentially the action of the game, well, is very weak. Most combat involves spinning Starfy into enemies, and, if done in quick enough succession, earns bonus star gems. It's very basic, and very easy. Starfy's only weakpoint in a spin-attack is that if done too rapidly, he becomes dizzy and needs to recover for a few seconds. Enemies only pose danger when they enter the screen without enough time to react because you're trying to swim through the stage quickly.
The game also takes Starfy's abilities and gives them out bit-by-bit. Unfortunately, this means the abilities are completely locked until you reach a stage where the abilities are necessary. At this point, you're shown a quick "How-to" cutscene, and suddenly Starfy can utilize the move. An example is the ability to run on land: Hold down the spin-attack button, and Starfy will zoom across the ground. The moves are very simple, and really, the game is simple enough that every ability could be open to the player at the beginning, but for some reason, non-story-related reason, they're locked.
When reading about the transformations, I always see praise, and I'll agree, just being in the Dragon transformation is better than Starfy's standard gameplay. There's typically more enemies on screen, you don't get dizzy from attacking, and rather than swim, the sections are all on land, so the game has less of an artificial feeling of exploration and more of a feeling of a platformer. This is definitely good news, and where the game would be most associated with most Kirby games.
All-in-all, I could not give this game a score. It wouldn't be fair to it. The game isn't for me. It's not likely for platformer enthusiasts. Go play some more Mario, Sonic, Kirby, or Donkey Kong Country, or any other platformer. This game is too easy and too simple for you.
Who is it for? It's for your son or daughter, who's never played a platformer before. It's for your mother, or grandmother, who doesn't know how to play a video game, or has only seen Tetris. For this type of crowd, the game might be just perfect, and couldn't be any better. For the rest? Don't waste your time, you'll be disappointed.