Ar tonelico: Melody of Elemia is a role-playing game that started a trilogy of games featuring unique combat, having standard fighters and spellcasters known as Reyvateils. While fighters are strong to attacks, Reyvateils are weak and must be protected from enemy attacks.
Players control Lyner Barsett, a young knight from Platina who is tasked with heading to the lower world and finding out how to stop Mir from escaping her prison.
Phases
The game is broken up into chapters known as Phases, with a possibility of four in total. Each Phase consists of a linear set of events that you much complete to advance, but backtracking is available through the world map.
Conversations
By completing certain conditions such as using a certain Reyvateils in battle or having a certain item in your inventory, you can gain a talk topic with the Reyvateils in your party. In order to view talk topics, you need to rest at a camp or inn and the available talk topics will appear. This small scenes make up the bulk of character relationships in the game and allow you to dive deeper into your Reyvateils soulspace.

Towns
Towns can not be explored openly, instead you will need to choose a location from the menu to enter a location, which you can then explore. Each town has at least one Shop, and Inn, and a Dive Shop.
Shops can sell items used for Grathmeld Synthesis, Healing Items, Weapons, and Armor.
The Inn is where you can heal your characters, view talk topics, and perform Grathmeld.
A Dive Shop is where Lyner can dive into the Reyvateils to increase their song magic.
Grathmeld Synthesis
Grathmelding is Ar tonelico's term for Alchemy, which is a recurring feature in all Gust games. The basics is that you select a recipe that you have the required ingredients for and then create the item.
The first thing you will need is a Recipe Card, which can be found or bought.
The next thing you need is the required ingredients, which can be dropped from enemies or purchased from shops.
The final item you need is a Grathnode Crystal, which you can purchase or find. The crystal's quality (not the effect, this is only useful for "Enhancements") will directly effect the strength of the item you create, making the crystal selection the most important part of Grathmelding.
Enhancements
Equipment can also be enhanced by using Grathnode Crystals. To do this, select a weapon in the Equipment menu and then go to Enhancements. Each piece of equipment has a different amount of open slots available to place crystals, but crystals can be changed at any time without worry.
Dungeons
Each non-town section of the world is considered a dungeon, which has monsters and treasure that hinder your path. Unlike many RPG with random encounters, Ar tonelico uses a system that is unique to Gust games. As you walk around a dungeon, a bar in the lower corner will start blue and turn red over time. The closer to red, the more likely you are to encounter a random encounter.
Additionally, once the bar is depleted by having a set number of random encounters, you're free to wander without worry of more encounters.
Towns can not be explored openly, instead you will need to choose a location from the menu to enter a location, which you can then explore. Each town has at least one Shop, and Inn, and a Dive Shop.