https://www.youtube.com/watch?v=nYwe_WHARdc
HQ version https://mega.co.nz/#!eRRiST6Q!ISuZ58MzXEb8cQD5XoBYrAVMqtI_35s42IKlyKkUbYE (.MP4 | 844 MB)
HQ version in case you couldn't get it from Mega or something
http://www.gamersyde.com/news_the_witcher_3_gameplay_trailer-16443_en.html