Gameplay
In Episode I, the player controls a party of up to three characters, one of which represents the group on the map screen. Players progress through the story by crossing areas and fighting various enemies and bosses along the way. Enemies are not encountered randomly; they patrol fixed locations on each map. When the player touches an enemy, he or she will enter a battle. Like most RPGs, battles in Episode I feature turn-based combat, which involves a numeral system that determines health (Hit Points), magic/mana (Ether Points), and damage. Status effects are common in Xenosaga, and feature both beneficial and detrimental effects. Benefits include increasing damage or defense, while detriments include falling asleep or being poisoned. Characters gain experience points after each battle and when a character obtains a certain amount of points, he or she levels up. When a character rises in level, his or her statistics increase accordingly, although there are other ways to increase them.
Episode I introduces several new features during battles. When a party member attacks, his or her "Boost Gauge" increases. If he or she attacks on a specific turn, this increase may be furthered. When the gauge reaches at least Level 1, that character may use the Boost command to "Normal Boost", which usually results in he or she immediately receiving a turn in battle directly after the present character. However, the enemy may use a "Counter Boost" to override this normal one. Each character can attain up to three Boost levels in one battle. During battle, players can board mechs called A.G.W.S.. Although the A. G. W. S. units generally feature special attacks and higher statistics, they are limited in turns, ammunition, and actions (for example, a character may not use any healing ethers or items when he or she is inside an A. G. W. S., also the A. G. W. S. will retain damage after the battle that cannot be restored normally). This system is similar to the "Gear" battle system from Xenogears. When attacking an enemy, a character may initiate a string of different attacks. However, the number of attacks that may be used is determined by the amount of Action Points (AP) that the character has stored. Characters usually obtain four AP at the start of their turn, but they can also save up to six unused points. There are items which can increase the normal 4 AP to 5 or even 6, allowing more actions to be performed. Different actions take different amounts of AP.
In addition to monetary and experience awards after each battle, characters will obtain Ether, Tech, and Skill points upon completing a battle. If the battle ends on the "Points Boost" turn, even more points will be rewarded. Ether points can be spent to obtain new Ether, or character-specific magical spells. Tech points are used to either increase stats, such as attack power, Hit Points, and dexterity or to improve the power and usefulness of Tech attacks. Finally, Skill points can be used to obtain special commands, status attack guards, or other features.
Episode I features no universal world map, but the player can travel to several regions of the game through the EVS (Environmental Simulator), a location replicator/virtualizer also seen in Episodes II and III. Other features include an in-game database, several mini-game "plug-in" systems that can be accessed from Shion's portable UMN console, and an e-mail system that allows players to make playful decisions that have little significance to the main plot. Episode I, 2, and 3 includes a treasure hunt side-quest, in which the player may find decoders for eighteen locked doors scattered throughout the game. The doors lead to various treasures and skills. The game map features a small radar that detects the locations of enemies and allies.
Read more about this topic: Xenosaga Episode I: Der Wille Zur Macht