Sorry for the bad quality, but I couldn't find better videos/pictures. If the animations don't load on Lemmy, you can watch them directly in imgur here: https://imgur.com/a/x8xJYmI
Cut Gameplay Mechanics:
- Companions (other than Issun or NPC's riding Ammy)
It might have been possible to travel with companions, like for example the Canine Warriors. Whether this would only apply to overworld travel or also to fights, isn't exactly clear.
- Frogs
Ammy could startle small critters by walking through high grass, possibly also while mowing it with the Celestial Brush.
- Fireflies
I have no idea why these were removed, when they would have added a nice nighttime atmosphere. The hardware back then (PSII) could definitely handle smallish flying objects all across the screen, as there are segments where cherry blossoms and/or leaves float through the air.
- BARK BARK BARK smack!
Funny but probably useless: while Ammy is still able to bark in the actual release, there was a gameplay mechanic to annoy people at night with the noise (even with a small "annoy-o-meter" on the screen) until they come storming out of their houses, trying to clobber Ammy. In the final release most (if not all) houses are accessible at night anyway so there is no need to wake up the residents.
Cut Areas:
Early gameplay trailers showed a lot of environments that never made it into the game, like for example a grey, rocky shoreline, an underground mine, a birch forest and a riverbed in a deep chasm. None of these appear in the finished game.
(Riverbed)
(Grey Shore)
(Mine)
(Birch Forest)
Cut Enemies:
- Gotouryu
This one wasn't even deliberately scrapped - the dev responsible for imcluding the enemy somewhere in the game simply forgot to do that. Oops![^1]
- Sanmenkubi
This enemy would likely have been a boss, and is similar to Orochi: a fixed, broad "base" with a bell on top, and multiple heads acting individually. Pictured here are only the heads atop long "necks", front view.
Cut Characters:
- Kuni
That little tyke was meant to be Susano's and Kushi's son. An illustration of him appears during the ending credits, but the in-game model wasn't actually used.
All in all there is a lot of stuff I would have loved to see in the game, but Ōkami is still a cool, relaxing game (and one of my all-time favorites) even without these "extras".
[^1]: https://tcrf.net/Ōkami_(Wii)#Gotouryu - actual statement is on twitter and linked here, but I am not willing to link that site directly.