Back on topic, Okami Wii isn't the hardest game so far, but I had a hard time with some of the brush strokes at first. The harder I tried the worse I was at it. I finally realized that I was trying to hard and fast. Slowing down I can now get them right more consistently. I'm still frustrated with getting the third sphere up to the bear.
Getting the third sphere up to the bear is difficult even with the PS2 controller. Even though it doesn't look hard, I still haven't managed to do it. That's assuming the third sphere is the green spiky thing... I've been away from Agata Forest so long that I don't remember which sphere I got up to.
But in general, Okami is an easy game. Makes me wish there was a Hard difficulty in Okami. Maybe there's not due to aesthetic reasons or having to focus on the single-player game (and who wants to playtest the game for a million more hours just to ensure a new difficulty isn't unfair?), but there's only a precious few moments in the game that are truly hard. And those moments are optional.
An example is the last Blockhead in the game (if you don't know what they are, you will soon enough), hidden in some obscure area. I swear that entirely depends on luck.
The second-hardest challenge in the game for me is the optional battle against the Canine Warriors really late in the game. I don't think it's humanly possible to finish that battle without refilling your health multiple times. Even with all the health-refilling items I had at the time, I was nearly dead at the end of it all. That's easily tougher than the final boss fight.