FFXI has changed a lot over the years as result of many expansions. This particular version only covers the first 3 of them, so I'll try to cover this game as best I can based on the first 3 expansions. Be warned, this is going to be big.
FFXI was at the time (and sort of still is) one of the most ingenius ideas by SE to create an MMORPG that could be played on the PS2. In order to achieve this SE had to create a special launcher tool known as PlayOnline which would act as a launcher for FFXI and other online games owned by SE (only 2 games were ever made for it and one got cancelled a few years later) and also to provide chat and messaging facilities similar to applications such as MSN and IRC. PlayOnline was also used for creating content IDs for character creation, account management, and ingame support. These days however most of those features were removed from the PlayOnline viewer and transferred to the web-based Square Enix Account Management system, so the PlayOnline viewer is now really just a launcher tool for FFXI with private chat and messaging systems, but in order to use the private chat and messaging systems you have to be logged out of FFXI since they are part of PlayOnline, not FFXI itself.
While it sounded like a cool idea to begin with the fact is most players hate PlayOnline. It's slow, it's got loads of menus just to get to the FFXI launcher itself, and before you can even begin downloading and installing the patches to play FFXI you have to download and install the patches for PlayOnline. The downloading and installation process is horribly slow and it must complete to 100% before the game will allow you to log in. If you get disconnected at any point (which can happen if a lot of players are logging in at once to download updates) then you'll have to start over again.
Once you are finally logged into FFXI and have created your character one of the first things you will notice when you log in is that there is no minimap. There is a radar which shows which direction you're facing, but it will not tell you where you are. There are larger world maps that only show you the current area you're in, but these only cover the starter city and region you've chosen to start in. Maps for areas outside of that region have to be purchased from map vendors (some maps are given via quests or found in coffers but the majority of them are vendor bought.) This is a heavy burden for new players who are already skint and their first quest only giving a measley 50 gil which isn't even enough to buy a low level item of clothing, spell or weapon.
Another thing you will notice is that almost all quests do not give you any experience points. Quests and missions are primarily for earning fame, gil and item rewards. Instead of questing your levels you'll be required to fight monsters, usually in groups with other players. You can solo your levels but once you get past level 10 it becomes increasingly difficult to solo monsters that give decent experience points. You will also discover that even though your levels will require more experience points to next level you will not get more experience points from higher level monsters. A tough monster to a level 1 will give you the same 250 experience points that a tough monster to a level 75 would give, but since a level 75 cannot solo a tough monster then they'll need to team up with others and that 250 experience points will be split among the other players. If the party is fast enough in downing another monster shortly after they will create a chain which adds an extra 10% experience points earned. The higher the chain the more experience points can be earned, however the time between chains will get shorter leaving very little time for rests, and the higher the level the monster the longer it takes to kill, resulting in a very slow grind to the next level.
You'll also notice monsters do not have any indication on first glance to what their levels are, nor are you given any hints to whether it is aggressive or not until you come into close contact with it. To determine the strength of a monster the player must target it and check it. Monster strengths are labelled as either being Too Weak, Easy Prey, Decent Challenge, Even Match, Tough, Very Tough, Incredibly Tough, or Impossible to Gauge, and each of these may also give an indication of their evasion and defense. A monster that checks as being Incredibly Tough with high defense and evasion usually means that this monster would be extremely difficult to fight even with a group, it may also be of an exceptionally higher level. A monster that checks as Impossible to Gauge means it is a rare and special monster known as a Notorious Monster. Even more powerful Notorious Monsters at level 75 and above are known as HNMs, the "H" has been argued that it stands for Hard, Hyper or Huge, but in the end it means it's not meant to be solo'd. Upon defeating the Notorious Monster you may get a rare item as a reward.
In addition to earning experience points, gil and items from fighting monsters there is also a rare chance of obtaining a Beastman Seal. These seals are a special type of currency used in the purchase of orbs that are used to enter one of 3 battlefields known as Burning Circles. These battlefields are small with a time limit and often with a single objective to destroy all monsters inside them. Most of them require more than 1 player to enter. Entering a Burning Circle battlefield (nicknamed BCNM) will temporarily de-level you to the level of the orb you selected on purchase. Rewards for completing a BCNM may vary from junk to extremely valuable items. If you leave the BCNM at any time you will not be able to reenter it, and if someone begins fighting before everyone else enters then they will be locked out and unable to enter until the BCNM is either completed or all players have exited. Using a new orb to reenter will create a new battlefield, so you cannot pick up from where you left off if you did not complete the previous BCNM. Also if your party wipes and you do not have a means to resurrect safely or you run out of time you will be ejected out of the BCNM and your attempt will be deemed a failure. You will not be able to reenter a BCNM with the same orb twice even if you failed it.
Fighting monsters in groups at higher levels is much more fun and efficient than solo since you can kill mobs much faster, chain them, and if you time your TP abilities and match their elements you can create some colourful effects called Skillchains which can do some pretty awesome damage. A mage who casts a spell that matches the element of the skillchain can also increase their own damage, resulting in a Magic Burst. You also won't need to /heal as often since this is the only way to replenish HP and MP other than from receiving cures, refresh, or using consumables.
Speaking of mages, you do not learn spells automatically or by talking to a trainer. Spells are learned from magical scrolls. These are bought from vendors or dropped from certain monsters. Some can also be quested. This makes leveling a mage class very expensive due to the cost of scrolls. Ordinary job abilities are learned as you level.
Ranged ammunition such as bullets, arrows and most thrown items are consumed on use. You need to be exceptionally careful if using thrown items that give you increased damage to not accidentally throw it at your target. There is no means to cancel the action other than to quickly /heal and hope you sit before you throw.
Beastmaster pets cannot be interacted by anyone other than a beastmaster. In order to heal a pet the beastmaster must feed it biscuits designed for healing pets. Once a beastmaster leaves a zone they will lose their pet. Pets that have been tamed in the wild will eventually cease to be friendly to the beastmaster and will attack them, especially if the pet was a high level one. When a wild pet is released it will either peacefully go back to its patrol area (providing it's non-aggressive to start with) or disappear. Beastmasters cannot tame beastmen or NMs, instead they will bind it temporarily giving the beastmaster time to escape. In absence of a suitable pet the beastmaster may use a jug pet. These will not go hostile against the beastmaster, they last longer, and can be more stronger than a tamed pet.
Unlike a lot of other MMORPGs which fix your job to the one you selected at character creation, FFXI allows you to play any job you want by visiting your moghouse or a moogle and changing job. When playing for the first time the player is limited to choosing between a red mage, black mage, white mage, warrior, monk or thief. Later on in the game the player can unlock other speciality jobs like paladin or death knight by completing certain quests. Also on completion of a special quest players can unlock their subjob. The subjob allows allocation of a second job which caps at half the level of your main job, so if you choose to set your main job as a 24 white mage and a subjob as a 22 black mage you will be a level 24 white mage / level 12 black mage, with all the extra mp bonus and spells of a level 12 black mage. Subjobs require to be leveled separately, so if you level up to a 48 white mage you will still have a level 22 black mage subjob.
You can also change gear whilst in combat, allowing you to utilize certain items of clothing that benefit individual skills. Changing weapons (including ranged items) will result in resetting your TP to 0. The major issue with this is that the more equipment you carry the less inventory space you have available, and even if you have something equipped it will still take up an inventory slot. You can increase your inventory capacity and that of your Mogsafe by completing Gobbiebag quests, these require high amounts of fame and lots of rare and expensive materials. You can also store unused equipment with porter moogles or storage NPCs for a small fee.
Should you accidentally aggro a monster or fight something too hard there is very little chance of escaping it if you attempt to run away. Monsters that are in hot persuit will continue to chase and hit you as you run, and nearby NPCs will not assist you. Some monsters persue via scent, so unless you can put a great distance between yourself and the monster and use deodorizers you will still be persued. The only option here is to run towards a zone line and hope that the monster gives up the chase otherwise you'll have to run into the next zone. Standard monsters that lose aggro will disappear if they've been pulled far away from their patrol area and respawn. Notorious Monsters will slowly return to their patrol area. Any monsters returning to their patrol area will slowly recover their hit points. Until it reaches 100% health the monster will not give full experience points to anyone else who takes claim of it. The other option is to Call For Help. Since claiming a monster binds it to you and your party nobody else will be able to assist you fighting it until you either invite them, lose aggro, or use Call For Help. Targetting and attacking another monster will also cause your previous target to be marked as unclaimed unless a different party member attacks it. Loot or experience points from targets that you no longer have claimed to will then go to the next person who takes claim of it. Calling for help will mark all targets that you've damaged or performed abilities on and will display their position on the radar for other players to see. Monsters that are marked will not give any experience points or loot when defeated. If the player who has used Call For Help causes the monster to lose aggro either by dying, zoning, or running away, the monster will no longer be marked and will either despawn or return to its patrol area.
Death has unforgiving penalties. You have 1 hour before someone can come to rescue your corpse. If you choose to release you will lose 10% experience points and be thrown back to your last saved home point. Different raise levels will restore some of the experience points lost. If you only just leveled up and the number of points lost is greater than what you currently have you will be de-leveled and any armor that you was wearing for that level will be unequipped. You will still retain any spells for that level but you cannot use them until you level up again.
Skills such as the various weapon types and magic require to be leveled up to be more effective. As you fight or cast your skills will increase by a fraction. Weapon skills and agressive magic spells such as nukes will only increase if you battle against monsters within that skills' level, not against your level, so even if you're a level 50 you will not gain any skill points fighting a level 50 monster if your skill is far too low, and you'll most likely miss most of the time or do no damage. Each job level also has a skill cap. The higher the level your skill gets the more longer it takes to gain a skill point.
Crafting skills also level in the same way as weapons and magic skills. Crafting an item has a chance of failure or success, both with a chance of giving you a skillup. Failure results in loss of the crystal used and a percentage of materials. The more lower level your craft skill is from the items' craft level the more materials you will lose. Also it is said that the moon phase in the game affects chances of success/failure, and having your moghouse decorated with furniture that is strong in the element of the crystal you're using will also improve your chances of success. As well as succeeding in crafting there's a chance of producing a higher quality version. This is also affected by the moon phase and your craft level vs the items' craft leve. The higher the level your craft skill is above the items' craft level the greater the chance you have at producing a high quality version.
In addition to leveling craft skills you will be required every 10th level to visit a guild of that craft to take a test and advance. If you do not then you will not be able to level your craft beyond its cap. You will also need to be a specific job level to take these tests. These tests will require you to hand in a craftable item which you can either craft yourself or buy on the auction house. Also you can only specialize in 1 craft (with the exception of fishing and synergy.) Once you reach level 60 in all crafts you will only then be able to reach 100 in 1 of the crafts or spread the remaining 40 levels over multiple crafts. You will end up needing to level other crafts as you will come across recipes that require more than 1 craft to produce it, such as a Mahogany Bed which requires level 60 woodworking and level 53 clothcraft. Any craft in FFXI takes a long time to level and you may reach max level in your jobs long before you reach max level in your crafts, and some materials or crystals needed will require you to be a certain level to farm them.
Upon reaching level 50 and every 5 levels afterwards you will be required to perform a certain test to unlock your levels and advance. These are only needed to be done once per character, so if you are a level 60 black mage you do not have to do those tests again with another job. Many of these tests require you to do them with other players.
Traveling around Vana'diel is limited to running, chocobo hiring, boats and airships. Chocobos can only be hired from cities or at crags and you only have a certain amount of time you can stay on them. The player controls the chocobo, it is not an automated journey. There are no private mounts that you carry with you to mount up anywhere in the world and you cannot ride a chocobo inside a dungeon or a city. Ships and airships require you to either pay gil to board or to also have a relevant pass. Airships going to and from Jeuno requires you to be a certain rank in order to be rewarded with a permanent pass. To be permitted to board the airship to Kazham which is a leveling ground for the level 40+ you'll be required to either purchase the pass at a very inflated price or to provide 3 chest keys obtained from fighting beastmen in the lower level beastmen strongholds. Ships and airships can be a long and slow journey, and you'll also have to wait for them to arrive at the docks to board them, but they are quicker than trying to get from A to B on a chocobo.
I mentioned earlier about furnishing moghouses and about Mogsafes. A moghouse is a private room in the Residential Area of a city or town which you can decorate and store items and equipment in a Mogsafe. You can only access items stored in a Mogsafe from inside a moghouse or from a Moogle if the town doesn't have a residential area. You can also get additional storage by decorating your home with furnishings that give extra storage slots. Items that are stored in the Storage can only be accessed from your moghouse in your home land, and you can only decorate your moghouse in your home land. Moghouses can also act as an indoor greenhouse for growing plants.
Rise of the Zilart expansion pack included the level increase from 60-75 and introduced new jobs, zones, quests and missions. It was one of the most largest and detailed expansions for FFXI. Included in the expansion was the nightmare world of Dynamis, a new endgame area Tu'lia (nicknamed as Sky), new NMs and HNMs, dragoon, ninja, samurai and summoner jobs, and avatar prime battles for summoners to get them as summonable pets. Like with beastmaster pets only their owner is able to interact with them, although unlike beastmasters a dragoon pet can be healed in the same way a player heals by using /heal, and when the summoner summons a new avatar it will have 100% HP again. A new currency of Kindred Seals was also added from fighting higher level mobs for entering higher level battlefields (KSNMs) similar to BCNM battlefields.
Treasures of Aht Urghan was the second expansion pack. This included a new higher level city that is constantly under seige by surrounding beastmen strongholds, and a whole new range of quests and missions that revolved around the city. There was plenty of new adventures which included new battlefields, salvage operations, einherjar, assault, chocobo raising and racing, and new jobs blue mage, puppet master, and corsair. 2 new special avatar prime battles Odin and Alexander were added for summoners.
While the ToAU expansion revolved more around its own history, Chains of Promathia was a continuation from Rise of the Zilart and delved more deeper into the history of Vana'diel and the mystery behind the crags and the Zilartian race. While there was no new jobs added to this expansion there was more zones added, quests and missions, a new endgame area Al'Taieu (nicknamed Sea), many new battleground areas that were mostly to do with the missions, and a new avatar prime battle Diabolos.