Innovative but with a major flaw.
The game incorporates this "Book of Prophecy," which I like to consider as your personal encyclopedia. Comparable to the story of Noah's Ark, you are enlisted to choose the things which shall carry over to a new world after the current world is destroyed--but instead of an ark to carry all the goods, you get a nifty book to do so. Playing as either a girl or a boy, you go through the different chapters smacking objects to record into your holy book. The main gameplay consists of navigating through dungeons, solving puzzles to get past each room. The puzzles aren't anything to write home for; most of them are just flipping switches & killing monsters in a set amount of time.
However, the game's amazing code system is what makes this game truly enjoyable. Every time you record something in the Book of Prophecy, you can view the genetic coding of the object and transfer its codes to another page. This allows you to weaken monsters, change the attributes of weapons, and make other characters' affection for you rise.
Sadly, the most innovative and fun part of the game is handicapped with a major flaw. There's no searching system whatsoever in the whole 2000 page book, and finding a specific code is a laborious chore. Also, you only get 4 slots to store your excess codes, so much switching around is required before you get your desired outcome.
Major gripes aside, Avalon Code is definitely worth a try. The music, storyline, and characters are charming enough to cover up its flaws.