Okami - First Playthrough

Ok, so I recently got Okami (PS2 version) through a trade so that I can finally cross it off of my gaming bucket list.  

My first impressions were amazing. For one, the graphics and gameplay hold up really well, but what really surprised me was how much of a Zelda game it is. When I started out you could not tear me away from the screen. I think I blew through the first 14 hours of the game over a weekend. 
I love the simplicity of the Celestial Brush. Instead of having to collect a bunch of items and constantly switch between them throughout the course of the game, they roll all your abilities onto this one button and twirl of the analog stick. I'm also digging the Capcom in-jokes (how is there not a Raging Demon page on the site??). 
Unfortunately though, my gushing love for this game has subsided, but only a bit. The thing that deflated me was the fake climax. When the game starts, you're told about this hundred year old legend of the defeat of a monster. The game constantly references this and felt like it was leading up to you fulfilling / recreating this task. Once the game made it obvious that this was about to happen, I was a bit surprised as I had not unlocked the majority of the brush techniques and there was a bunch of stuff missing in the various log books, but the story made it feel like it was time to do this. So I went through the "final" dungeon(s), felled the beast of legend, and the game kept going. 
I would assume the feeling is akin to what SotN players felt when they discovered there was a whole 'nother castle to explore to truly beat the game. 
I'm still making my way through the game, but now it feels more like a grind. I'm sure this is mostly my fault and perhaps a sign of the times. I was expecting a 20 hour game, which was about the mark I hit when I reached the first climax, and was a bit intimidated when I realized that I had barely scratched the surface. 
Thinking about it now I'm in awe at how much they've been able to cram into this game. 
Apologies for my disjointed thoughts, but I'm really just curious if anyone feels the same. 
Also, I'm still making my way through the game so NO SPOILERS please.