This is the title on the resource itself--screen, menu, label, packaging. If these are different, pick one and record the others as variant titles using hasAlternativeTitle. If your system allows it, record the source from which you took the title.
Some systems may designate a part of the title string as a subtitle, however, game titles seldom have true subtitles, so the colon and string following the colon should be included as part of the title.