One of the most under-rated and under-appreciated historical total war games on release. And like the historical period it covers (4th century to 8th century), it remains under-appreciated by many in the total war community (including you Creative Assembly).
Almost 10 years later, many veterans of the historical total war franchise only play Attila (and bit of Rome II) due to its great basic economy, battle, and climate systems for community mods.
Thankfully, the fanbase took charge and developed Attila where CA fell short.
Attila is home to many historical total war scenario mods covering vast time periods. Attila fanbase created historical scenarios from the fall of Carthage (Ancient Empires), the fall of Western Roman Empire (5th century Fall of the Eagles), the last attempt to restore the fragmented West Roman Empire (Age of Majorian), the Last Roman reconquest of Western Rome (6th century with Belisarius and Justinian in the Eastern Roman Empire - Age of Justinian), hypothetical Roman 5th century crisis (Terminus Total War Attila), the rise of the first Islamic caliphate (Age of Emperor Heraclius and fall of the Sassanids in 7th century - the Last Persian), the rise of the last Sassanid great king (Age of Khosrow II), up until the 4th crusade in the 13th century (Medieval 1212 AD). (I might have missed a few still).
Attila Total War had a buggy launch and poor optimization. It could not live up to the polished Rome II and the huge community the former attracted and held, but it was unique in its design, fresh concept, environment, and mechanics.
Attila Total War introduced to the total war franchise:
-Horde (migratory tribes community) mechanics, horde is your army. But it is not only your border defences or offensive force like in past total war titles, but also "your culture's survival" with horde buildings (like a mobile settlement), faction economy, agent recruitment, army recruitment, and mere existence of a faction on the grand campaign map.
Horde battles have thin margins of error (getting a horde or migratory tribe wiped out means your faction becomes significantly weaker, and in some cases, one battle away from defeat if your remaining horde is defeated). Every move must be calculated lest you find yourself cornered and surrounded by enemy doom army stacks in a hostile land. Balancing the ledger also isn't easy, your income often depends on how fertile the land is while your horde is migrating through.
-Razing mechanics - want to put an entire enemy settlement to the sword and leave nothing alive behind? Well you can, by razing aka "let none live." In fact, it's the Huns factions' favourite past time. Resettlement after a raze takes ages (reflecting the slow return of the population).
-The game is harder than previous total war titles. You are given a bucket to bail out a sinking ship with most factions.
-Climate Change - your land would not be fertile enough to support your culture forever, and going on migration south into foreign empires might be your best option.
-The Hunnic Scourge (the impending doom aka abandon all hope) - for many factions, the Huns invasion (like the Mongol and Timurid Invasion) is "arrival of death" itself. Most culture's unit rosters will not have satisfactory answers to full stacks of mobile skirmishing horse archers and shock cavalry lancers (rip Vikings, gothic tribes, desert kingdoms, and to a lesser extent, WRE). The Huns are so terrifying in fact that they bring with it a huge morale penalty when fighting against it with Christian factions.
But then Eastern Roman Empire (particularly, its elite Tagmata regiments and Clibanarii shock cav regiments) be like: Yo, hold my wine and olive oil, imma go smack that Hun horse archer boi real quik.
-Sanitation - public order is no longer dependent on taxes, absence of wars/destruction, raiding parties, and religion. Your must ensure your settlements have sufficient sanitation to keep it clean, otherwise, disease will ruin your population growth and economy. We distinguish "civilized" and "uncivilized" in Attila through smell only.
-Migration/settlement - many factions allow the player to "pack up your culture" and move elsewhere - no longer are you firmly wedded to your starting region. You can settle your people in a safe and fertile land far from your culture's ancestral land, and build an empire there, just like the Visigoth, Ostrogoth, and Vandals did historically.
-Horse archers are incredibly useful and dangerous. Battles can be won by "feigned retreats" and "kiting" the enemy by spamming light horse archers. Heavy infantry and cavalry melee are no longer the only way to win battles. An army of horse archers skillfully "micro'd" can assassinate generals, whittle enemy infantry down to bits, and shred enemy heavy cavalry. Lack of ammo is your only enemy.
-War Weariness - in Age of Charlemagne DLC - aka various negative faction effects from constantly being at war (and losing battles). Think twice about declaring war on everyone.
Attila Total War was the last great European-theatre historical total war released. It shook up the decade long basic historical Total War gameplay formula, which can be summarized as "start small, build an army, build an economy, secure resources, win battles, and expand." It's difficult to steamroll in Attila Total War, especially if the huns have multiple hordes when Attila takes over.
Instead, Attila challenges you to "survive" either as crumpling empires (the Romans) with countless enemies in your heartland (such as Gothic migratory hordes), with attack on multiple fronts (Africa, Gaul, Asia Minor, and the Levant) without adequate field armies to check advances. The celebrated Roman legions of Augustus are no longer invincible on the battlefield where heavy infantry once held sway. In Attila, cavalry and mounted skirmishers have the initiative in battles.
Rome (whether East or West) starts out on the defensive unlike past Total War games.
The migratory barbarians, the gothic tribes, start off on the offensive pillaging and plundering rich Roman lands to reach a new home somewhere deep within Roman territory (Pro Tip: Hispania has all you need).
Others look for opportunities to profit from the weak, overstretched, and defenceless Roman empires, like Rome's historical enemy Parthia (now the Sassanid Empire), the emerging vikings, the invading Huns and White Huns, and the awakening African/Arabian kingdoms.
Every faction in Attila has its weaknesses like Medieval II (some in early game, others in late game, some permanent impairments, some temporary impairments).
To be sure, Attila in its vanilla state is a little "barebones" when it comes to faction unit variety. The barbarian Gothic factions have similar playstyles and army rosters (almost like copy+pastes of each other). The mighty Sassanid Empire (its army roster) is oddly bland and weak considering its historical significance as the arch nemesis of Rome. The viking factions have little differences in playstyle, and the desert kingdoms feel flawed in their individual ways.
Nonetheless, Attila TW has two excellent DLCs - The Last Roman and Age of Charlemagne. The latter come close to what "Fall of the Samurai" was to Shogun 2 in gameplay content and mechanics. The former gives every men out there a chance to restore the former and O.G. Roman Empire by subjugating the barbarians, through force ("how dare you stand where Rome Empire stood").
In conclusion, I have played Total War from Rome I. Rome I, Attila, Medieval II, Napoleon, Three Kingdoms, Shogun 2, and Empire will forever remain my top historical total war games.
We were born too late to save the Roman Empire, but born too early to start a Roman Empire in space, so at least we can try to save the Roman Empires on our PC, and mourn the fall of Emperor Majorian (the Last Roman in the West, where men cried).