In going back through some ROM-translations of older games, however, there is one game that is different in many ways; a game that first created many innovations that show up sporadically in other fire emblem games.
Fire Emblem: Gaiden.
The first big change, a MASSIVE change, is the way items and weapons work. You can only ever have one item or weapon at a time, and instead of having durability, the equipped weapon simply change's a unit's stats and/or capabilities. If you don't have any weapons, you will just attack with a "basic" weapon, at your basic stats. There are also no consumable items like vulneraries or elixirs, meaning the only healing you get is from clerics, healing squares, or equipment which heals you over time.
>>> This is the change that truly makes Gaiden different from any other Fire Emblem for me. While it takes out much of the depth of carrying multiple items and conservatively using your best equipment, it also makes every item choice carry more weight, and allows additional item types to be experimented with, such as rings and shields.
Because of the change to weapons, spells have also been drastically changed. Instead of being based around an equipped item, spells use up HP to cast, and each magic-using character learns new spells after they've leveled up a certain number of times.
>>> This is a change I surprisingly liked a lot, after I got used to it. Sure, mages are less durable, but there's always inexpensive healing, be it through recover spells or health-regenerating items, and by the end of the game you get at least a half dozen rings to heal yourself with. Plus, it allowed tactical use of every spell for every given situation. Things like Warp, which I almost never used in other FE games due to the 5-only limit on the staff, became a staple in my strategies in Gaiden. My only complaint is that the "weight" and power of the spells themselves aren't listed, meaning you have to figure it out on your own how much damage a spell does, and how much it slows down your attack speed.
Instead of the usual, linear mission path, it features only five chapters, each of which open up a new part of the overworld, with new battles and enemies. Some caves and graveyards have respawning enemies, meaning you can grind for experience endlessly. Some enemy forts or other locations occasionally spawn enemies which aggressively roam the overworld - If you attack an enemy with these reinforcements, they will be added in a separate group to the fight. If they roam into your party, they will attack you on that map - you will be placed where the enemies were when you first won the fight, and the roaming attackers will get the first turn.
>>> I like some aspects of this, and dislike others. On one hand, I like having the ability to do things in different orders - an open overworld provides branching paths - and it helps give a lot more shape to the world, where sometimes the mission-to-mission gameplay makes it harder to tell. On the other hand, having an open overworld encourages grinding, meaning certain battles will either be far too easy or nearly impossible, depending on how much grinding of side-missions or optional battles is done.
Having talked about items and grinding, I now have my number one complaint about Gaiden - some of the best items in the game (the Sol, Luna and Astra lances), as well as extra Angel rings and Dragon shields, can ONLY be obtained by grinding enemies for an OBSCENELY LOW drop rate. Sure, the game is beat-able without them, but it requires more level-grinding. Basically, it's grind until you get to a good level, and possibly get a lucky break on nabbing an item, though I killed hundreds of thieves, zombie dragons and gargoyles and never once found any of these items.
Speaking of awful rates, the RNG is the most cruel random number generator I have ever had the misfortune of dealing with. Instead of the system used in FE6 and onward (i.e. all worldwide-released games) where it rolls two numbers from 1 to 100 and averages them, it rolls only once. Why is this bad? Because without good item stats, support, or ANY unit with high skill. it's almost impossible to get to a 100% hit chance, and if you don't have that 100%, you're going to be missing a LOT of crucial attacks. The good news is the enemy misses a lot as well, but this makes the game feel much more random than newer FE games.
While we're on the subject of bad RNG, though, unit level-ups are terrible. In most FE games, something like a 40% growth is pretty poor. In Gaiden, 20% is the average, so 40% is a godsend. On the bright side, I think the game is rigged to always give you at least one stat increase (at least, I've never had a completely blank level-up), but with rates like this, all but the best units will average out to one, MAYBE two points up per level, and it will usually end up being just +1 HP.
That said, though, this brings us to two of my favorite things about Gaiden - the 3-tier (usually) progression system, and the two-party split. Both reappeared in Radiant Dawn, and are why that game still competes for my #1 spot despite not having real Support conversations.
First up, the two-party split. Both Alm and Celica's parties are entirely separate from one another, only being allowed to trade a small number of items at set points in the game via traders in villages. Not only does this allow a focus on two very different parties, but it works GREAT with the overworld map system, since you need to carefully manage the positions of both parties - after all, the enemy forts can still mass and send armies against the party you aren't using at the time! This is probably my favorite bit of Gaiden, and though it was done to a small extent in Radiant Dawn, I really wish they combined it with an overworld map again.
As for the 3-tier progression, every unit, except spellcasters, Alm and Celica, or pegasus knights, has three "tiers" - a basic tier, an advanced, and then their ultimate tier. Unlike in Radiant Dawn, however, the enemies start showing up in higher tiers from very early on, and by the end you are only fighting monsters and tier 3 units.
While I like the tier system, the advancement is a bit weird. Instead of using seals, or automatically advancing after hitting level 20, you go to an Angel Statue and class-up from there, getting certain stat bonuses to put you to the "minimum" for that class (so class-up bonuses can be somewhat gamed, though you're almost always better trying to level up as much as possible before classing up, just like always).
The classes themselves are:
Pegasus Knight -> FalcoKnight
Soldier -> Knight (armor) -> Baron
Mercenary -> Myrmidon -> Dread Fighter -> Villager*
Cavalier -> Paladin -> Gold Knight
Archer -> Sniper -> Bow Knight
Mage -> Sage
Sister -> Saint
Every class has, arguably, their own special abilities. FalcoKnights automatically deal max damage against monsters, and are probably the strongest class of any because of that - though they, along with Sisters and the main character classes, are a class unreachable to Villagers. Barons don't really have anything notable, but their massive defense and power make up for that and their limited movement. Gold Knights have 9 movement and above-average stats. Bow Knights can attack up to 5 spaces away even without equipment. Dread Fighters have surprisingly high movement, and can re-class back into Villager, keeping their stats and allowing them to change to a mage, archer, cavalier, soldier or back to mercenary, for potentially endless leveling! (though it's almost entirely unnecessary to do so, as the game is fairly short)
Finally playing this game to completion, there are things I certainly both love and hate about it. However, most of what I dislike is due simply to the archaic limitations of the NES. If they were to remake Gaiden for a newer platform (or at least take even more elements wholesale from it), I would certainly appreciate it.
