Every hand movement and action (drinking a can of Coke) was tested by a real person to get it looking as lifelike as possible. Also attention was given to the veins in Ryo's hands.
The Shenmue series, as envisioned by creator Yu Suzuki, is made up of at least 16 chapters. The original Shenmue only covered the first chapter, while Shenmue II contains four chapters of the series. However, chapters included in Shenmue II are chapters 3 to 5. Chapter 2 is in neither game and only existed as part of a manga spinoff titled "Shenmue: Side Story" (originally published in the Japanese publication, Dorimaga). In this chapter, Ryo saves a little girl from Chai (the villain from the first game), who infiltrated the ship Ryo was in. This explains some of the dialogue between Ryo and the girl's mother in the beginning of the second game.
Shenmue was originally supposed to be a Virtua Fighter RPG type of game.
It took around 5 years for AM2 to finish the original Shenmue. The sequel took much less since the game was originally intended to have all chapters in a single game.
Microsoft struck a deal with Sega to have Shenmue 2 to be exclusive to the Xbox in the US. As a result, Electronic Boutique imported the PAL (European/Australian) version of Shenmue 2 for the Dreamcast and became one of the most imported titles in history and is the only import game ever to be sold at Electronics Boutique. As a result of this, the Xbox version only achieved moderate success.