Pre-orders When you pre-order a game, you're paying for it upfront based on a marketing campaign or glossy pre-release trailer. Before the game releases, you have no reviews, footage from YouTube or Twitch, or other impressions to go off.
This is a problem because game trailers and other advertisements are not always true to the game's final form. No Man's Sky is the best example of this in recent years.
Released in 2016, No Man's Sky is a procedurally generated space adventure game that the developers claimed could create up to 18 quintillion planets. It started off as a small indie venture and quickly grew into a much-hyped game when Sony got involved.