We say 'parts' instead of 'items', to reinforce the isPartOf machinery.
Thanks Thad for the suggestion, http://lists.w3.org/Archives/Public/public-vocabs/2014Nov/0127.html
Also some whitespace padding.
trailer domainIncludes VideoGame.
Thanks Aaron, http://lists.w3.org/Archives/Public/public-vocabs/2014Nov/0129.html