Odin Sphere is a fairly unusual game for the PS2. The premise is the player will play through a series of books that are divided into individual chapters. When the game starts the player chooses which book they want to play which determines the character they get to use as well as the setting.
The game is played in a two dimensional side scrolling view that wraps around on itself. If you go far enough in either direction you will end up back where you started. Levels vary in size and enemies will come at you from the air as well as the ground often with many packed into a fairly small area perfect for an AoE attack.
When you start a book you are in a safe zone populated with NPC's who will speak their lines if you talk to them. Access to the adventure area(s) is through clearly marked exits. Shortly after entering a hostile zone enemies will start to appear. Enemies come in waves with the next wave not starting until the current wave is defeated. Combat is typical platform style with lots of running, jumping and mashing of buttons to guard, attack and use items.
As you defeat enemies they may drop coins or other small items as well as little blue lights that float around. The little blue lights (called phazons) are a combination of experience point and fuel for your special moves. By pressing a button you can draw all phazons on a level to you and absorb them. Each one you collect advances your level gauge as well as charges your power bar until it has been filled. In addition phazons can be used to grow plants from seeds you place in the ground. The plants ripen after absorbing a set number of phazons and various types of fruit can be harvested depending on the seed.
Fruits can be eaten to restore health and they will advance the level gauge. Different foods have different levels of heath/xp benefits. Fruits can also be taken to one of the restaurants and made into a more valuable type of food if you have found the recipe and have all the required ingredients.
The game also has an alchemy system. By collecting hidden (but easily found) creatures called mandragora and empty flasks a player can create potions that do damage to the enemy, cure or prevent status ailments, restore health, or grant xp. Before you can make a potion you must discover the formula. Through a process of combining items and flasks into higher rated containers you can cause phazons to be released when the potion is made garnering you more xp and restoring your power gauge.
Each chapter of the book is a series of levels linked as a series of interconnected rings. Once you beat a level you can choose which path to take to the next ring. As you go you build up a map of the chapter which shows you the rings you have been to, their difficulty rating and what the reward is for beating it.
The amount of time it takes you to defeat a level as well as how much damage you take doing it are used to calculate your score at the end. Depending on your score you will receive a letter grade. The higher your grade the greater the reward you get at the end. Rewards are given to you in the form of a chest which you break open like a piñata to collect the items inside.
Each chapter ends in a boss fight and one or more cut scenes which reveal the story. There are no grades or rewards for defeating the bosses other than the ability to progress further through the tale. Once a chapter of a book has been beaten it is possible to go back and play that chapter again to acquire more experience or items. Once all the chapters of a book have been beaten the next book and its character become available to play. You may play books you have already beaten though there seems to be no reason to do so since each book has its own character.
The uniqueness of the game is entertaining for a while but long before I finished I grew tired of running levels and mashing buttons. There is no particular feeling of exploration or discovery since you are very limited in where you can go and the levels themselves are simply arenas for fighting monsters. The story was mildly interesting but quite ponderous and melodramatic.
Unless you are really bored I wouldn't bother with Odin Sphere. Rent it or pull it out of the used/bargain bin if you are really curious.