Freesound Forums

Hello,
I am writing a game right now and, naturally, need sounds for it. I guess this question has been asked a million times before, so, my apologies for being a repost zombie.
I saw a sound noted with this term "This work is licensed under the Creative Commons 0 License.". Is it correct that I may use that sound in my game, even if I am going to sell it? I just want to make sure. There could be samples inside it which belong to someone after all. Should I contact the author and ask for a sort of insurance?
Do I give the author's name in the credits? Depending on the finished game, he might not even want to be mentioned. So, do I have to contact him and ask?
As you can see I know nothing of this topic, so please enlighten me.

https://creativecommons.org/publicdomain/zero/1.0/

So free to use