I was excited to read The Flood because I really enjoyed the Fall of Reach (the first Halo book) and was looking forward to a new installment in the Master Chief's adventures. The great thing about the Fall of Reach was the creative license taken by that author to create a new universe and to explain the origins of the Master Chief as well as the war with the Covenant. Unfortunately, The Flood is more of a walk-through of Halo, the video game, then a good story. In my opinion, the author abandoned artistic license in his attempt to reproduce a level by level description of the game. At many points while reading the book I found myself wondering if the author wrote the story based on notes he took while watching someone play the video game.
The story-line in the book suffers from several major defects, including, but not limited to: (1) stilted adherence to the many missions and sub-missions found in the video game, including the necessity in many cases that each wave be separated by a door which the Chief must open, (2) the inclusion of automated non-player dialog found in the video game, (3) repetitious battle scenes between the Chief and the unending waves of enemies attacking the Master Chief (even the author starts describing these as "all too familiar"), (4) repetitious descriptions of weapon selection (switching from shotgun to rifle and back again) and reloading, (5) the Master Chief's unexplained inability to carry more than two weapons at time, even for short distances (even though the armor provides him with enough strength to flip over a jeep laying on its side), and (6) the ever present availability of reloads and replacement weapons. These aspects may make for great game play, but they make for a lousy book.
A better story would have been one which follows the essential elements of the game's story line but which provided a more detailed account of the actions taken by the Master Chief, the Marines and the Covenant.
When a movie is made into a video game, the video game must make certain sacrifices from the original story so as to improve game play. The opposite is also true: an action oriented video-game does not contain the level of character development necessary to support a written story line. In the case of The Flood, the author should have eliminated most of the game-play scenes (which provide minimal detail and maximum action) and created a more detail oriented story with better story and character development. I would recommend another of the author's books "Legion of the Damned" as a good example (think: The French Foreign Legion in space).
Do we really need chapter after chapter of the Master Chief shooting up wave after wave of the Flood, then Covenant, then Protectors, then all three combined? Much of this could have been eliminated in favor of a few strong chapters of story development. The story is so stilted in remaining loyal to the game that an observant reader can almost detect where level changes and cut scenes would have occurred in the video game.
I strongly recommend against this buying The Flood and I do not consider it to be a true sequel to the Fall of Reach. Play the game instead, you'll get the same exact story either way. Buyer beware.