A few weeks ago I sat down with a finished story mission from Dawn of War 3. The mission united the Space Marine captain Gabriel Angelos with the Imperial Knight, Solaria in a mission to push the Eldar back, form a base, and then shut down the huge portal the Eldar are using to bring their armies onto the planet's surface.

Once the base was up the whole map was available, and I was free to capture resource points and take out the Eldar gates in the order of my choosing. The map was made up of a series of open areas, gated by cliff faces and Eldar shield walls. The Eldar used webgates to launch regular raids on my base from three directions, and ambush forces laid a neat trap around a westerly resource point, hiding out of view on the surrounding cliffs. The mission culminated in a fight with a huge Eldar force, led by their newly revealed super-unit, the huge wraithknight.

I ran the mission several times, and managed to get a feel for how the Space Marines operate in Dawn of War 3. Army building is a vital component, and I was impressed with the variety of forces you can build, even within this single faction. I tried a traditional combined arms mix of infantry, robots and tanks, but had even more fun attempting quirky builds (all Dreadnoughts all the time, servitors as scouts) to discover the Space Marine army I enjoyed using the most. It involved a lot of heavy weapon devastator squads and judicious use of the giant orbital laser ability. By the end of the hands-on session, thousands of Eldar were dead. It was a good day.

If you're looking for an overview of how the single player is structured, how elite and line units work, how elite hero units differ from line units (they're redeployable on a cooldown timer, rather than built at base), what Relic's design aims are and more general info, check out our initial preview feature. Here I'll get stuck into the Space Marine army itself to take a look at how individual units function. The game isn't out until next year, so roles and abilities are subject to change. It should hopefully give you a sense of how the army works and how Dawn of War 3 plays.

Tactical marines

The Space Marines are the Emperor's finest, but some are less fine than others. That's not to say that tactical marines are poor. They're just, well, fine. They are resilient for line troops, but didn't seem to do meaningful damage until I gave them plasma weapons. They can also take flamers, which look amazing, but have a short range that makes them difficult to deploy against the quick Eldar.

Tactical Marines are mainly good for sitting on a capture point while your serious units dent the enemy. Against the Eldar I found that I only needed one or two squads. Resources were otherwise better spent on heavy weapon teams.

It is fun to use tac marines as bait sometimes, however, if you can find a way to taunt an enemy into charging when you have a bunch of heavy weapons squads overseeing the area.

Upgrading a squad's weapon loadout gives all squad members a new weapon. In the fiction only one or two members of a tactical marine squad get the good toys. Here the upgrade choice is intended to fully specialise them. Relic wants every unit on the field to have a clear role.

Good for: Sitting on points, burning chokepoints, slowly whittling down enemy infantry. Plus it's nice to have some Space Marines running around, isn't it?

Bad for: Getting anything done without backup.

Heavy weapons crews

These guys are awesome. The devastator's heavy bolter is a huge belt-fed machinegun that you'd normally find bolted onto the back of a truck. Select Space Marines who have taken their vitamins wield these in underslung posture. They are intended as an anti-infantry squad, but multiple units focusing their fire can trouble larger units such as wraithguard.

As with heavy weapons units in Relic games, heavy weapons crews need some setup time. These guys need only seconds to settle and start firing—seemingly quite a lot shorter than previous heavy weapon crews in DoW 2 and Company of Heroes. When I had two or three of them sat behind some tac marines, the Eldar struggled to get close, especially when the devastators focused fire on individual units. You can put lots of them in heavy cover points, which is a disaster for the enemy if they have no close combat units to hand.

There's also a lascannon variant that kits out a unit with anti-vehicle lasers. Sustained fire increases the power of their beams, and I found that I didn't need many to counter the occasional appearance of one of the Eldar's skimmers.

Good for: Most things. As long as there's some fodder in front of them they even seemed decent used aggressively.

Bad for: Close combat of any kind. Also, running onto a point to cap it, unless it's heavy cover—in that case the risky dash might be worth it, but honestly probably isn't. keep them in the shade at the back. they like it there.

Assault marines

Assault marines wear jetpacks that let them strike from above, scattering enemies and butchering anyone in the same cover as them. Their strike ability feels amazing to use, especially when you're sending them into cover, or into a line of weak shooters, of which the Eldar field many. They are designed primarily to boss enemies out of cover, but in a pinch I've sacrificed them to disrupt the Eldar back line and stop heavy weapons focusing down my imperial knight. Their ability to hop up cliffs gives them good flanking opportunities that other Space Marines lack, but they are quite fragile, and seem to need support from heavy melee (assault terminators and/or Gabriel Angelos) if you want them to make a serious incursive strike.

Good for: Clearing out cover. Looking awesome while clearing out cover. You can kinda scout with them if you keep their jump ability in reserve and use it to escape when they get into trouble.

Bad for: Taking on the enemy solo. They struggled to take capture points without support. I found that it's a good idea to jump them right out of combat if things aren't immediately going their way, they're more fragile than they look.

Dreadnoughts

Fiction-wise, my favourite unit. The dreadnought houses the mind/spirit of a heroic Space Marine severely wounded in battle. They are endearingly boxy tools of vengeance who waddle comically into enemies and then horribly dismember them.

They have a charge move in Dawn of War 3 in which they get really pumped up and excitedly penguin-dash toward the enemy line. For this I love them, even if they're quite easily killed. They mostly melted in big battles, but in time I think I could find a use for them supporting individual tac marines in resource point grabs, or as base guards to stop melee enemies from taking out defensive turrets and heavy weapon defenders.

Good for: Looking awesome, sounding awesome, occasionally making enemies explode in a cloud of blood. Their knockback stomp ability also syncs with Gabe's hammer special to keep enemies off their feet.

Bad for: Vanguard duty. Also most other things at the moment.

Whirlwind tank

This is our first look at tanks in Dawn of War 3. The whirlwind is a long-range artillery piece that lets you target the ground to launch fierce bombardments. It's effective, but not as obscene as the Imperial Knight's insanely good bombardment attack, and the extra micro requirement deterred me from building too many of them.

A better player would do very well with them, however, particularly because their bombardment can hop over walls and cliffs to soften up hard-to-reach enemies. Tanks in Dawn of War 3 are weak to attack from the rear; their tooltips make a point of it. The Eldar flying heavy weapon squads serve as an obvious counter.

Good for: Ambushing ambushers hiding on cliffs. Wrecking the enemy's back line where all their heavy weapon guys tend to hide.

Bad for: It doesn't do much else, but what it does, it does well.

Assault terminators

These are an elite unit that you can upgrade throughout the campaign, and they are hard as nails. Their teleport ability is slow to recharge, but amazing. If there is a problem unit on the battlefield, they will kill it outright, or keep it occupied for a considerable time. I found that pairing them with Gabriel Angelos was a very good idea. In combination with the dreadnought's stomp, Angelos' hammer attacks and the Terminators' abilities, you can effectively juggle enemy squads with knockback. This could be huge in multiplayer, and is quite fun in singleplayer. I can't wait to do it to some large Ork units.

Good for: Mashing up enemies in cover, mashing up enemies out of cover.

Bad for: Standing nakedly in front of enemy heavy weapons fire doing nothing. As long as you don't do this, they're probably fine.

Heavy bolter drop pod

As a Space Marine player you have three drop pods that you can load up with units. You can bring these drop pods down onto the enemy, crushing them and giving you instant deployment to a battleline.

Alternatively, you can build a drop pod that carries four huge automated turrets that unfold on impact and start blasting everything within range. Multiples of these can mince up the poorly armoured Eldar infantry, including dangerous melee units such as banshees.

Eldar players are going to despise these things. They cost a fair chunk of resource and they fall apart after a minute or so, but in the right situation these could be better than dropping troops, and there's very little the enemy can do about them.

Good for: Annihilating infantry blobs.

Bad for: Taking on armoured enemies.

Imperial knight

This huge mini-titan is another hero unit, like Gabriel Angelos and the assault terminators. She's amazing. She has a huge health pool and her ranged attacks are good at killing pretty much everything. She can even swat down a melee unit if they're crowding around her feet, by punching them with her twin gatling cannons. This is not recommended as her primary mode of attack however.

Her best move is her bombardment ability that lets you target six missiles. Put all six of them on heavy cover or a big enemy unit and that's pretty much the end of that. Spread the missiles out and you can devastate an infantry line. If Solaria overheats, the missiles leave puddles of molten slag behind to deal damage over-time. The bombardment ability is a game-winner, and it feels amazing to use.

Good for: Range. Swiftly purging everything that isn't a space marine, in the name of the emperor.

Bad for: Dealing with multiple units in close combat. She will eventually go down to concentrated anti-vehicle fire, and she's too huge to hide behind stuff.

Gabriel Angelos

The leader of the Space Marines in Dawn of War 3, the returning series hero is a veteran, and has the combat chops to match his experience. He's spry for an ageing fellow. Anyone who can somersault in terminator armour with a huge double handed hammer is worthy of leading a Space Marine force. This is is primary closing move that can help him get into a line without getting shot, and he will get shot a lot. The Eldar seem to understand that he's the boss, and will mercilessly pour shuriken fire into him if you let him lope slowly toward the enemy.

Fortunately Gabe's other special move reflects projectiles, which gives heavy wraithguard troops something to think about. Against a small force I found I could let Angelos go about his business, dismantling Eldar line troops for fun. In bigger fights, his relative toughness is very useful as long as he has some bodies around him. Paired with assault terminators, he can barge into a flank and deal damage the enemy can't ignore.

Good for: Hammering everything but a huge super unit. Even then he'll give it a go.

Bad for: Charging into the line alone, even though he totally would without a second thought.

Giant space laser

It's not technically a unit, but it feels like one. Every 300 seconds or so you get to call down a blast from an orbiting imperial vessel. You right-click to move it around the battlefield. Enemies it touches will become trapped in its gravitational pull and eventually dissolve in the heat.

The space laser deletes armies. It's as simple as that. It's a great big eraser with 'NOPE' written on it that you move with slow but horrifying certainty around the battlefield. As it claims more souls, it gets fatter, slower and more powerful. That means that small units have a narrow chance of escaping, but large slow units are, as the God-Emperor might put it, "thoroughly f***ing smited".

Good for: Winning.

Bad for: Toasting marshmallows without overdoing it.