I'm having a bit of trouble with the big giant tentacle monster. I've managed four times to kill 3 of it's tentacles and after that there's a brief cutscene and qte moment. But after that, I've no idea what to do. It keeps throwing rocks at me, and I can't go anywhere, except hide behind the pieces of broken bridge.

you have to go and kill the 4th tentacle and then complete the qte :P

im stuck during the qte as it seems i am unable to complete it.

What 4th tentacle? I don't see anymore tentacles with the orange thinggy.

You have to pin and sever three tentacles, then one of the middle tentacles will sweep. I decided to avoid that one to pin and sever the last tentacle but I'm not sure if it matters.

When the sweeping tentacle comes hit the right mouse button to hop on, then repeatedly tap the left mouse button when prompted. After it fills you'll ride the tentacle for a few seconds then you'll be prompted to hit the space bar. Geralt will jump off and the tentacle will hit the bridge.

The bridge will topple and you have to run up the ramp created by the bridge, then when you get the the top Geralt will automatically finish the job.

geralt is grabbing the tentacle automatically for me and after i've filled the bar he just gets thrown off without the prompt for hitting the space bar ever appearing.

Eight attempts so far, this is beyond idiotic. Maybe one of the developers would like to explain how doing the same thing over and over again is supposed to be enjoyable. It might be a little better it the camera was used to show the player what is happening rather than used for dramatic shots of the enemy, that combined with yet another moronic QTE session do not make for a fun encounter. I play games for enjoyment, and I'm not enjoying this at all.

Run up the ramp? OK, I will try that.

Try to keep to the middle area of the ramp after you get close to the top. That started the cutscene for me.

I do agree, the battle is abit insane. i got 20x tries and so far i got to the bridge only, where i was heroically killed by a flying boulder.
You can use Quen btw, it will absorb 1 tentacle hit.

About the Kayran: There's supposed to be a trap, for which Cedric's selling a recipe. During my visit to Loredo's estate somebody told me I could find a part for said trap at the back of Loredo's mansion in a crate on a wooden platform. I'm pretty sure I found the crate, but it only contained orens.

Is that a bug, or is the game telling me that everybody lies?

Edit: Never mind. I was looking in the wrong place at night and when I came back later the crate was gone.

Same i can trap and kill the 1st 2 tentacles , then Yyrden seems not to work anymore what am i supposed to do please help :(

Only the tentacles with the glowy bits are trappable. For some reason, I get the distinct impression you are trying to trap the two middle tentacles, which coincidentally do not have glowy orange bits on them. ;p You'll note only the left two and right two tentacles do.

Ty lol! now is a cake i even killed twice because the 1st time i didn't drink the potion , so i reloaded for the extra exp , ty very much :)

WOW! thats what was wrong! seriously thought my game was broken for a second

I was really enjoying this game up until this point, but i have to say, this is not enjoyable, it just feels like a broken QTE fest.

That said i hope i can beat this thing so i can move on.