Okami is absolutely the best Zelda-clone ever made about a sun-goddess inhabiting the body of a wolf statue and using the magic power of calligraphy to beautify the natural envronment. Hands down.
I mean, there's no question. Even if you're a fan of one of those other goddess-wolf-calligraphy games that we see so many of these days, you're going to be forced to concede that Okami delivers far more than its competitors just in the realm of art style before you start getting into any of its gameplay innovations.
Nothing else looks like Okami. Where other games push for photorealism, Okami decides that the appropriate look for a videogame should be a mix of shadow-puppetry and traditional Japanese woodcuts. And then renders the whole thing in a kind of hallucinogenic cell-shaded 3D. Things don't appear as what they are so much as icons of what they are. People are vague suggestive shapes; scenery is rendered in the manner of flowing brushstrokes; monsters are malformed malevolent scribbles. The hand of the artist is visible in each and every image on screen.
All this artistic eccentricity flows right into the gameplay. You'll play as the sun goddess Amaterasu, who has taken command of a statue of legendarily heroic wolf Shiranui in order to combat an evil darkness spreading across Nippon. Amaterasu can use all of Shiranui's wolfy abilities, including sprinting, hole-digging and the rending of flesh, but more relevantly she also has the power of the Celestial Brush at her command.
By holding down a shoulder button, you can stop time, and turn the scene in front of you into a hand-drawn parchment. Then you can draw on it. For example, executing a straight horizontal-ish line across the scene will deliver a devastating slash which will overcome monsters, topple trees, and cleave stones. Drawing a circle in the air will bring forth the sun and turn day to night; the same circle on a plant will bring it into bloom; and if you add an extra line to the circle reminiscent of a fuse then you'll summon into being a mighty explosive to break down barriers and devastate your opponents.
Okami overcomes the bane of many games that use a drawing system - the symbols you'll be drawing are easy to handle and the game is intelligent in interpreting them. It matters not if your circle is drawn clockwise or anti-clockwise, or whether you start at the top or the bottom; slashes can be made on pretty much any plane except straight vertical and can go left-to-right or right-to-left, et cetera. (The bloom power is occasionally a little frustrating, but you'll rarely have any time pressure when using that one.) The fact that time stops when you're drawing is a huge help.
You don't start with all the brush techniques at once. Instead, you pick them up from various celestial beings as you go about your travels. In this way, the game is very similar to The Legend of Zelda, as you'll be picking up a new ability, using it to overcome a challenge, and then getting a new ability as a reward (rinse, repeat).
Your quest will regularly take you into caves and dungeons, but the developers seem not to have understood that the very best bit about what they've created lies on the overworld. Each new section of overworld you encounter is initially possessed by a creeping darkness that has turned the land into a barren wasteland. As you use your powers to perform various tasks in each section, the wasteland will be driven back until eventually the area is a paradise once more.
Your first task is usally to bring into bloom a sacred tree in each area, which sends a wave of rejuvenation running across the land, making the blight retreat to select pockets of nastiness. This all by itself is an incredibly cool and satisfying cutscene, as flowers and greenery rush across the landscape like an unstoppable tide.
Once you've made the area vaguely safe to traverse, you can then seek out the individual trouble points and use your abilities to fix them. Blighted grass can be healed by colouring it over with your rejuvenation power. Water can be made to flow by linking clean rivers to empty or blackened ones with lines of your brush. Animals can be fed with a variety of foodstuffs. Dead trees can be brought back to life with a touch of your brush. This gameplay is simple but deeply rewarding, as the results of your actions are instantly and integrally reflected in the landscape, which you'll be moving back and forth across as you complete your quest. Every item around you is a reminder of your challenges and successes.
The game would ultimately be a better game if it had stuck entirely to this overworld-rejuvenation gameplay, because the dungeons are ultimately deeply derivative of The Legend of Zelda and more than a little dull. They're reasonably well executed for what they are, but you'll be left feeling like you've played them a million times already in other games, where they were done better. Each one predictably culminates in a boss fight, which are at least rather well executed, if a little easy.
The plot is pretty poorly paced. The game opens promisingly, with an excellent narrative that binds your fate to that of the village drunkard on a quest to defeat the evil serpent-demon Orochi. However, twelve hours or so later, when you've defeated Orochi, you'll be thinking that that's a reasonably good place for the game to end, with most plot threads tied up - but you'll be wrong. The game springs a "but that's not all!" on you, and immediately flings you off on another quest just when you were thinking that you'd probably had enough of Okami. Myself, I was a bit disenchanted with all the dungeon crawling, and frustrated by the plot bait-and-switch, so as of this writing I haven't progressed very far into the second quest, and it's possible I never will.
If you love the 3D Legend of Zelda games and want more of the same gameplay in a very different-looking package, then Okami will be like a wonderful gift from the heavens. Even if you're not, you have to see this game to understand just how wonderful it looks. But if the Zelda gameplay wearies you, then you'll be disappointed that Okami didn't trust in its own innovation enough to abandon the rather tired Zelda formula.