There is no reason it has to be more than 5 minutes. 30 seconds to introduce yourself and what game you'll be reviewing. A minute to lay down the introduction to the setting and story without spoiling anything past maybe the first hour. A minute to talk about the characters. A minute to talk about the gameplay. 30 seconds to talk about pros. 30 seconds to talk about cons. 30 seconds to give a final thumbs up, thumbs down and an outro. Done. Be concise, don't prattle on, give the gist without spoiling it