29. A title must be playable to completion. No user or program error should prohibit the game from continuing. If you make a stupid move and get eaten by a dragon and the game ends, you have played to completion. If you make an incorrect move and the game freezes up or prohibits the continuation of play, it is a not move that shouldn't have been made, it is a bug. 30. A multiple player option should be in every recreational product. Where it makes sense (certain sports and arcade games), two-player simultaneous play is a requirement (e.g., hockey and football). 31. Simulations must attempt to match the real world in as much detail as possible, including the standard rules of play in sports games.