Final Fantasy II is equally audacious and infuriating in its design, with its merits and flaws stemming from the same design decisions. This game can't seem to succeed without stumbling, with praise immediately followed by "But the thing is...". Likewise, it can't fail without also inspiring thoughts of how forward thinking it can be and without causing one to lament what could have been. To play FF II is to gnash your teeth with a smile, and to laugh with a broken rib.
Even if you've never played this entry you've likely heard tales of its asinine leveling system, which I'll address in a moment. Much like Zelda II, the creators of this second entry in a now-venerated series decided to mix things up perhaps a bit too much and succeeded only in leaving a permanent pall over the entire game. I've met people who have never played Final Fantasy II yet still know of its reputation as arguably the worst in the series. After asking if I mean "Final Fantasy IV" or the real "Final Fantasy II" and clearing up that whole mess, those individuals inevitably follow up with "You don't level up in that game, right?"
Yes and no. In short, there are no experience points: you don't gain levels or the stat boosts that would normally accompany them. Instead your various attributes increase through use, e.g. strength increases through physical attacks, your health increases once you've taken a certain amount of damage, your MP increases through expenditure, etc. Every spell and every weapon type does have a level which affects its potency, but the points for increasing those levels are also acquired through repeated use as opposed to defeating enemies. It's a fascinating system which sets this game apart from any other in the mainline series, though ultimately for the worse.
The shortcomings creep up on your gradually. In fact, "leveling" as it is presented here is entertaining at the start, with initial stat increases coming quickly and bearing significant fruit. Simply making your way from Point A to Point B for the opening quest will see your party's health increase from tens to hundreds of HP, your attack power will receive perhaps the most appreciable boost in FF history, and your soft stats (attack, spirit and the like) will pop off like they're holding a block party. In those opening moments you'll be tempted to call bullshit on any rumors you've heard about the game. So what if there aren't actual character levels? Receiving small, incremental stat increases to the abilities you're actually using beats the hell out of grinding out an arbitrary number of battles to receive a boost to all your stats at once. Isn't it better to receive 10 HP a minute instead of 300 HP every half hour? While those stat increases begin to slow down after an hour or two of play, that's to be expected. What isn't expected is the moment where your character progress comes to a complete halt.
The way Final Fantasy II's character progression is setup means that you will eventually be unable to gain any further progress through organic play, i.e. simply fighting the enemies you encounter in your travels will do nothing for you. There's comes a point where the enemies you are currently strong enough to face are unable to provide any meaningful increases to your stats. They can't inflict enough damage to raise your health and defense, they die too quickly to provide more than a handful of skill points to raise the levels of your spells (more on that shortly), and they can't provide any additional skill points toward further leveling your weapon affinities. The only way to make any meaningful character progress is to sit down and kick your own ass.
You see, Final Fantasy II doesn't care where the damage comes from, or who you target with your spells and attacks: it only cares that you're taking damage, or attacking, or casting spells. You will spend a majority of your playtime ignoring low-level enemies while your party members punch each other in the face and scorch each other with spells before healing up to go for another round. Only once you've run out of MP and can no longer heal your party members do you actually kill the enemies. Then you rest at an inn and repeat the cycle over and over again.
This process is tedious on its face, but it's exasperated by just how long meaningful progress can take. Most bosses are effectively immune to physical damage (as they are just regular enemies from later in the game, and require much higher weapon skills to hurt than you can currently acquire), requiring you to have at least one adequately leveled offensive spell to inflict any damage. Your characters don't have levels, but your weapon skills and spells do, and raising one spell by a single level requires roughly an hour of dedicated casting. Even buffs (berserk, haste and the like) need to be leveled or they run the risk of missing when cast on your party members. With each spell maxing out at level 16, kitting out your party with a full complement of magic requires a time sink seldom seen outside of MMO's.
This may be the worst grind in the series, but hold onto your butts because it gets even worse. Though you have room for four party members, only three are with you throughout the entirety of the game. Your fourth slot is reserved for a rotating cast of fresh faces, most of whom are with you for only one or two story beats before departing and few of whom can match your party for power at the time you meet them. Not only are they unable to match the strength of your three permanent members, they are seldom strong enough to match the enemies you are encountering when they join (Gordon is the most egregious example). Later games in the series get around this by having new party members join at or around whatever level your current party is it; the fact that there are no character levels here means that they all have a default kit which rarely proves adequate. You can level them if you like, but they are bound to leave just as they are getting up to speed, effectively leaving you with only three party members for the majority of your adventure.
This system is downright infuriating, and is perhaps more so because it could have worked. A traditional leveling system, with experience points and all-or-nothing stat gains, often feels detached from how you play a game. However you choose to play a certain character, the developers pre-determined their stat growth, meaning they may be powerful sorcerers despite never having learned a cantrip. The idea of a character growing stronger in those disciplines they regularly practice is exciting, and proven by the Elder Scrolls titles. That series features a very similar system of character progression, but succeeds at it by granting improvements at an appreciable clip and not requiring you to play the game in a counter-intuitive manner.
Hell, Final Fantasy II can be looked at as a precursor to the Elder Scrolls series. Not only does it feature a very similar (if markedly worse) progression system, the world you are given to explore is remarkably open-ended for its time. Though the story is linear and there is nothing by way of story content outside of the main quest, you can traverse ~75% of the game world on foot right from the beginning. At one point I even walked my way to the next story beat by complete accident: I thought I was still on my way to the boat that the NPC said I needed to take because I would "never make it there on foot." The only thing stopping you from acquiring Holy and other end-game items right from the start are the multitude of enemies who do not want you in their backyard yet.
That world is also populated with characters possessing, well, character. They have names, histories and relationships, and they all have a stake in the war that is ravaging the world. Rather than Final Fantasy's largely hapless citizens who were strangely disconnected from the events around them, nearly everyone you meet has lost their freedom, their home, or a loved one to the enemy army. Your main characters aren't simply four nameless heroes fighting for a largely anonymous world, but four war-torn friends racing to stop a marauding empire. These elements are rudimentary here, but presage the narrative significance the series' later entries.
The sting of playing Final Fantasy II is all the worse because the promise on display; but where Final Fantasy delivered on its promise and elevated that game above its shortcomings, FF II bungles its system of character growth so thoroughly that it taints the game's promise and successes. I'm not certain that I can recommend FF II, but I can't condemn it either. If you are opposed to RPG grind on principle then stay far, far away; but if you are willing to brave it then a truly unique entry in the series awaits you.
Final Fantasy II is hamstrung by an unintuitive system of character progression which overshadows any strides made elsewhere in its design. It stands out from any other game in the series, but for all the wrong reasons.