well if it makes you happy the weakness of the first boss was told me trough hint sign instead of the game straightly telling me and in the end there was a little twist that i had to figure out
spoiler (click to show/hide)
the boss weakness is that you have to slash him on his navel when he comes out of water,when he comes out of the water the 3rd time,he has a cloyster enemy protecting his navel and you have to remove it by making it bloom,of course i'm not sure how much it counts since the game tells you before that you can make cloystery enemy bloom