The AOTR mod has done the impossible: it has made land battles fun. I love land battles. They are also incredibly frustrating to defend against. I wish to share some of the knowledge I have gained in the hopes that players will be more inclined to engage with land defenses.

I have no mouth and I must type: this is a very long ramble. Here is the TL;DR:

• On paper, land battles favor the attacker by default.
  
• The attacker will have superior numbers, and the attacker will predominantly use infantry.
  
• The effectiveness of defensive structures is unique to each planet and highly dependent on context.

It is not the intent of this guide to mislead the player into thinking that every planet can become impenetrable. Indeed, as we will see, some planets are basically doomed to die once they have lost space control. Instead, this guide is meant to give advice for players who absolutely insist to protect a planet from land invasions, caveats included.

Due to the sheer variety of land battles, I figure it is best to list the “ingredients” of land battle logistics, so that the player may become a “chef” rather than a “cook,” and know how to handle each situation unique to the context of their campaign. It is vital that the player understand the various weaknesses and limitations of land defenses, of which there are many.

I can’t tell if the AI has any logic behind its land invasion compositions. I will say that the AI attacks with pretty much everything it has in its inventory: often a mix of every unit in their raster. This means that, if your defense garrison has a weakness, the attacker will likely have something to exploit that weakness. If you have no anti-air, you will die. If you have no anti-personnel, you will die. If you have no anti-tank, you will die. If you have no way to counter artillery, you will die. In other words, to maximize the effectiveness of a defensive garrison, it must be a versatile mix of multiple unit types capable of covering every possible vulnerability.

There is a term I’ve heard in the Age of Empires community for exchanging kills and casualties with your opponent, called “trades.” Generally, a good trade is when you inflict more kills than you take losses, or kill more expensive units with a more economic force.

When it comes to the AI, any concept of “trades” is almost completely one-sided against the player. The AI gets practically infinite money, even on the lowest difficulty, plus the occasional sprinkle of free units to boot. They also do not adhere to the population limit. Suffice to say, the AI losing a t3 heavy tank is not the same as when the player loses a t3 heavy tank. The AI can replenish their losses quickly and effortlessly; the player, by comparison, cannot; at least not to such a degree as the computer.

It is my opinion that, when analyzing battles, the player should not consider enemy losses with nearly as much weight as their own. I have seen the AI perform land invasions with upwards of 40-50 units, and managed to kill all of them; and in just a few weeks, the AI will do it again as if nothing had happened.

The survivability of the player’s own troops is paramount to success. If intending to protect a planet from invasion, a failed defense with a “good trade” is simply unacceptable. If the player desires victory, they must aim for complete and total victory.

From what I can tell, the AI trains units on basically any planet they control, regardless of what units are available. Most factions have garrison posts that double as infantry training facilities, and factories are limited to certain worlds, which I think contributes to the overproduction and over-reliance on infantry relative to other units. Personally, I am particularly annoyed by the Rebel AI’s tendency to spam tier 0 rocket infantry, which are surprisingly effective at removing defenses when they have upwards of fifty of them at their disposal. Still, in that sense the AI has a trait that is predictable, and therefore easier to counter. Invest in anti-infantry!

Sometimes, a planet will be equipped with a planetary gun, such as an Ion Cannon or Hypervelocity Gun. This gives the defender an edge in space battles, and forces the attacker to move quickly and aggressively to minimize casualties from these weapons.

In land battles, the tables are turned completely. As the attacker has already gained space superiority, they have access to two powerful tools: Bombing Runs and Orbital Bombardment. These usually require a capital ship or bomber craft to be in orbit, which is almost always the case already, and comes at no extra cost to the attacker.

Bombing runs can technically be countered, but in practice is not always tenable. Once the bombs are dropped, most small-medium targets are destroyed, while larger targets take significant damage. Even just a couple drops from a single bomber will vaporize infantry and turrets. It is effectively a middle finger to any well-constructed defensive position.

Orbital Bombardments are less accurate by comparison, but are basically unavoidable damage unless the player has a Shutter Shield Generator (more details on ground structures later).

Thankfully, it is not in the AI’s programming to just hold back their troops and bombard the defender to death. All the same, the occasional bombing run / orbital bombardment thrown in with ordinary attacks is quite lethal; at least without proper defense.

It’s worth noting that there is virtually no limit to how many units you can stack in space. Sure, there’s a pop limit during a space battle, but you can call in reinforcements from your stack whenever needed. This is the same both for the attacker and defender in space battles: if the stack is big enough, either team can call in reinforcements during a battle.

This is not the case for a land garrison. A maximum of 10 units is allowed, which correlates to the number that the attacker can deploy at any given time. Unlike the attacker, however, the defender cannot stack any more units, and so is unable to call in reinforcements should they take losses.

Even if a land defense battle is successful, the player cannot reinforce the planet with additional (non-stealth) troops until the airspace is reclaimed by friendly ships. Due to the AI’s tendency to build more fleets in greater numbers and at faster speeds than the player, it may not be possible to immediately respond to a blockade. Thus, a land garrison must not only be able to defeat overwhelming numbers, but also take virtually no casualties, as they may not be able to receive relief for some time.

I know land and space battles are fundamentally different, but I will be making one or two comparisons which I think are relevant. Even without the comparisons, we will see that land defenses are fundamentally difficult to implement and easy to exploit.

For most factions, the Garrison Post doubles as a production center for their most basic units (usually infantry), and also has a decently-sized garrison that automatically replenishes for every instance of a land invasion. It is my understanding that garrison posts will eventually have randomized garrison compositions per instance of a battle, just like space stations.

A default space station has upgrades which can provide a significant boost to combat performance. Garrison posts do not have such upgrades; no land structure does. Additionally, space stations do not occupy any space structure slots, while the garrison post takes up one land structure slot. This is doubly significant when one observes that planets with high space infrastructure have up to six space structure slots; while on the ground, it is very rare for even a high-value planet to have more than five structure slots.

Consider this, also: Shield Generators and Turbolasers require the presence of a Power Generator to function. In other words, if at least one of these defense systems is present, then at least two structure slots must be occupied.

This would be somewhat equivalent to requiring a mobile support station or sympathizer outpost to be built in order to construct any more powerful stations. The comparison is not linear, as mobile support stations and sympathizer outposts still provide some additional abilities, while the Power Generator is a completely inert structure that does nothing on its own. Again, this is made more significant by the lower average number of land slots compared to space slots.

Ultimately, a good land defense comes at the sacrifice of additional economy / production, and so the player must pick and choose what planets are worth defending, and what planets are worth the risk of capture.

Now, how useful are turbolasers and shields in land battles?

Unfortunately, the answer is a big fat “it depends.”

For starters, the quantity and positions of turbolasers, shield generator(s) and power generator(s) is hard-coded to each planet.

A turbolaser might be stationed on an impenetrable mountain watching over a command post surrounded by trenches… or it could be sitting on some desolate island where it will never see combat. Some planets have up to 8 towers; others have as few as 2.

A shield generator may cover several major points of interest; or it will be in such a poor position that it may be genuinely unwise to build it in the first place. Some planets have up to 3 shield emitters; others have the standard 1.

Most crucially of all is the Power Generator, which is responsible for keeping both shields and turbolasers operational. At worst, the Power Generator may be so isolated and vulnerable that the attacker can and will head directly to the power generator and destroy it without ever engaging the shields and turbolasers. There are a handful of planets I’ve documented where the power generator placement is so incredibly poor, that I would just advise advancing the front to another world, or not bother attacking such planets in the first place, as they’re objectively difficult to maintain control over. Again, this isn’t to say it’s impossible, but it would require particular attention and effort, and without the guarantee of survivability compared to other worlds.

Another thing I think worth considering is the natural defenses of planets: objects that exist regardless of player-built structures. These are build pads, bunkers, civilian buildings, mercenaries, walls, trenches, etc.. The exact number and positioning of these objects varies wildly for each planet. Planets such as Hoth and Commenor will have several layers of walled trench lines supported by multiple bunkers and build pads; while some planets may only have a couple trees and some space hillbillies with pistols. Unfortunately, several of these objects are not visible in galactic view, but there is an ongoing effort to properly map these details on the AOTR wiki.

Because each of these defensive structures have their strengths and vulnerabilities, the best way to ensure the effectiveness of a land defense is to use multiple defense systems in unison. The principle is similar to deploying multiple different units in the garrison: by using more systems, the number of weak points generally diminishes.