Hi!
I'm really puzzled. I had read a lot of dudes that beat the Kayran "avoiding his tentacles" after chopping down 4/6. BUT, my Kayran start throwing boulders like 1/s with a 100% accuracy so, if I get out of a covered area, I got instantly killed. Anyone knows anything about it even the game guide doesn't say anything.

Right after the cutscene where the bridge collapses on it, do your best to place Geralt to the far left side, as close to the ramp you're going to climb on to finish it as possible. Then you'll just need to avoid those two pesky tentacles as you make your way up.

But as I mentioned I´m not getting attacked by tentacles. I´m getting ROCKS trowed at me that make impossible the way up. Even rolling even running from one side to another.

<ok, the trick is the order.... inner left - left - inner right - right

No trick at all. You did remember to drink a swallow before the fight right? If so just stand behind the rock in the center and regen a fair amount of HP. Then cast the Quen sign and get up there. Getting hit with Quen up shouldn't instant kill you. Once you get to a certain point on the downed bridge it shouldn't throw boulders anymore. Move up dodging the tentacles.