Over at Dead or Alive 5's Official Page, Team NINJA has posted a mini-manual to the demo including some of the system properties, character bios, and a small section of the character's move lists.
In addition, they have provided the link to give them feedback on what you think of the demo or system shown in it. So if you are(n't) happy with something, feel free to voice your opinion to them as they are providing a line of communication to provide your thoughts.
The Dead or Alive 5 Alpha Demo comes inside the Ninja Gaiden 3 Collector's Edition packaging as a downloadable code. Ninja Gaiden 3 will be out in America this Tuesday, March 20th, and in Europe on Friday, March 23rd.
Source: Dead or Alive 5