A.1  The short version. Arm and Core have the same kinds of buildings and nearly the same kinds of units, built from the same metal and energy. The difference is in the feel. Arm units tend to be a little faster and a little lighter. Core units tend to be a little tougher and a little slower. Arm wants to hit you where you aren't. Core wants to walk straight through the front door. That's the rule of thumb everybody uses, and like most rules of thumb, it's right more often than it's wrong.

A.2  Which side I play. Arm, about three games in four. I learned on the Arm campaign and I like a fast army. When I play Core it's usually because somebody on the Boneyards told me I'm a one-trick pony, which is fair.

A.3  Mirror matches. Arm against Arm and Core against Core come down to economy and micromanagement. Everything in Sections 2 and 3 applies double.

A.4  Peewees against AKs. The first kbots off the line. They're close enough that the player who builds more of them, and doesn't run them into a laser tower one at a time, is the one who wins the fight. A pack of eight to ten Peewees coming in early is the most common Arm opening on the Boneyards, and an AK swarm is the Core answer. If you see either coming at minute three, a light laser tower or two and your Commander standing behind them will hold, and he's just spent a lot of metal on nothing.

A.5  Flashes against Instigators. The fast light tanks. Both are built for raiding: you send a handful around the side of the map and kill his extractors and his builders while his army is somewhere else. A Flash raid that kills four extractors at minute six can win the game outright. My rule: every base gets at least one tower near the far-out extractors, and I keep a few units at home. It's boring. It works.

A.6  Artillery: Hammers and Thuds. The artillery kbots out-range towers. If somebody turtles behind laser towers, a few of these behind your front line will take the towers apart without losing a unit, as long as you keep something in front of them. Alone, they die to anything that touches them.

A.7  Anti-air. Jethros for Arm, Crashers for Core, and the missile trucks (Samson and Slasher) for vehicle players. Build some. I'm putting this in every section of the manual until people stop losing to bombers.

A.8  The main battle tanks. Stumpies for Arm, Raiders for Core, and they're the backbone of most vehicle armies through the middle of the game. Raiders take a little more punishment. Stumpies get there a little faster. In a straight-up fight of equal numbers I'd rather have the Raiders. In a game where I can choose the fight, I'd rather have the Stumpies.

A.9  The advanced units. Once both sides have advanced factories, the matchups get more lopsided, and this is where Core starts to feel like Core. The Reaper and the Goliath are heavy, slow and very hard to kill. Arm's answer is the Bulldog, and also the Zeus, a kbot with a lightning gun that is wonderful up close. On the Core side, the Pyro and its flamethrower are a nightmare for anything light that wanders into it. Against a Goliath column, I don't fight it head on. I hit it from the air or I go around it and hit his economy while it's walking toward my base.

A.10  The air war. Freedom Fighters and Avengers are the fighters, Thunders and Shadows the bombers, and the Brawler and Rapier gunships come out of the advanced aircraft plants. Gunships are what most people underrate. A dozen Brawlers circling over a line of tanks is a sight, and a dozen Rapiers circling over my tanks is a sight I've seen more often than I'd like. Fighters clear gunships and bombers. Gunships kill ground units. Ground anti-air kills everything that flies. Keep all three in mind and you'll be all right.

A.11  Big Bertha and the Intimidator. The long-range plasma cannons, Arm's and Core's. They throw a shell most of the way across a normal map, and every shot eats a pile of energy, so you need a serious economy behind one before you build it. Once one is up and firing at your base, you have two choices: kill it, or build so much that you can afford to lose a building every so often. Usually you kill it, and that usually means air, because it's sitting in the middle of his base where your ground army can't get to.

When should you build one? When the game has settled into a standoff and both sides have big economies. When should you not? When you've got 40 metal in the bank and a Flash raid coming. I've lost more games building a Bertha too early than I've ever won with one.

A.12  Defensive plasma. The Guardian for Arm and the Punisher for Core are the plasma batteries, and on a choke point they'll hold off a lot more than they cost. They can't do a thing about aircraft, and a big enough push will still get through, so don't think of them as a wall. Think of them as a very expensive speed bump.

A.13  The Annihilator and the Doomsday Machine. The heavy energy defenses. They kill almost anything big that comes close. They also cost a fortune to run. On ranked one-on-one games you will see these far less than you see them in the computer skirmishes, because the game is usually over before anybody has the energy for them.

A.14  The Core Contingency gave Core the Krogoth, a walking fortress of a kbot, enormous, slow, heavily armed, and very expensive. Arm doesn't get anything like it. The first time one walked into my base, in a game I thought I was winning, I sat there and watched it take apart a dozen Bulldogs and two Guardians before I had the sense to do anything else.

A.15  What I've learned about fighting one.

• It is slow. Every minute it spends walking to you, you can spend hitting the economy that paid for it.
• It is expensive. If he built a Krogoth, he didn't build a lot of other things. Look for what's missing.
• Don't feed it units a few at a time. Either throw everything at once or don't fight it at all.
• Air, and lots of it, has worked better for me than anything on the ground.
• If you see the Core player building something enormous and slow, that's your signal to attack now, before it's finished.

A.16  Some games on the Boneyards are set up without the Core Contingency units, and some people won't play anybody who builds a Krogoth. That's their business. I'll play either way, but if you're Core and I'm Arm and the game has the CC units in it, I'm going to be watching for it from minute one, and so should you.