No doubt about it – Primarch is rough!
I would recommend playing through at a lower difficulty to know what to expect, especially on the Angel Gate and Last Stand missions.
Here are some general recommendations for the war:
1. This is a different RTS in that you don’t have to right click targets, concentrate on strategic placement of units. Have your keyboard mapped and memorize your squad number, so you can immediately control the individual untis.
2. Use cover at all times. Avitus will gain an ability increasing his squads rate of fire under cover and this will keep your squads in the fight. Without cover expect your units to die very quickly.
3. Plan a leveling strategy for all units in advance, ensuring they compliment your overall battle tactics.
4. Learn to use Cyrus wisely – he is an extremely powerful character, but won’t last long on the front lines.
5. Be patient. Retreat is your best friend and hit it quickly when ambushed.
6. Take a sec to hit an optional mission if there is a reward that will help you out. Also ensure to take hold of strategic assets to aid your endgame.
The individual missions are nothing special, make sure to equip your troops based upon the intel provided: Anti-armor for Orcs and Eldar will come in handy, but not effective against the Tyranids. The two missions that will take the most time and planning are Angel Gate and Last Stand.
Take control of the closest beacon and move your troops across the map slowly and cautiously. Have your commander take point, keeping ranged support close behind for immediate suppression and cover fire support. I used Tarkus, Avitus, and Cyrus (sniper) for my playthough. Rescue all guardsmen and take all generators before attempting to close the gate. During the mission you will be ambushed by raveners and orcs, however by now you will be used to their tactics. Use Avitus’s increased rate of fire to finish enemies off quickly and Tarkus’ grenades and melee tactics. Keep Cyrus behind, but close to revive fallen leaders and support.
Once you have everything cleared head to the gate – take note of the two indestructible buildings flanking the gate control. Place Tarkus and Cyrus in one and Avitus in the other. You can also drop your commander in one as well for cover, or leave him in the open for support. Be quick on the retreat button as any exposed units will be quickly overwhelmed. Start to close the gate and move away. Spores will begin to descend in waves and you will have plenty of warning from Derosa as well as the markings around the gate. The ranged troops will mow the invaders from cover and the guardsmen will continually spawn from the South and assist, although they won’t last long. Lob grenades with Tarkus, snipe with Cyrus and use the increased rate of fire with Avitus. Just sit back and let your troops mow through the Carnifexes. Once they stop spawning take your force commander and secure the gate using cover fire from your support squads.
You get the whole compliment of squad commanders, so load out everyone prior to dropping.
Move to the first beacon and place your ranged troops in good cover ensuring overlapping fields of fire. Place one tarantula in medium range to absorb some of the waves. Leave your dreadnaught near the vein and take advantage of his amazing ranged support. I set up Tarkus in terminator armor with the missile rack to add to the long range support. I prefer the rally flag on the force commander as this gives a great emergency heal. Mines don’t do enough damage, but grenades, demo packs, and artillery are fantastic. Poison the first vein and closely monitor the battle, heal when necessary and shift fire to the brunt of the attacking forces.
Move to the second vein and stage your forces in advance just as you did before, although the attacks are increased and elite units more numerous. Place your remaining tarantula guns here. This is a good time to eliminate some of the nearby nests to reduce reinforcements. Once through the waves, the hive will die and you just need to hold out. If you are being overwhelmed, this is a good time to pull Cyrus back and stealth until support arrives.
You will be prompted to secure the beacon on the pyramid structure near the center of the map – cake walk. Secure and hold for a brief time and you will receive additional support from Angelos, your deciding factor in this fight, so pay close attention to his abilities and their locatoins. Move to the prompt on the map to the Hive Tyrant Alpha and prepare to succeed where the Eldar failed.
Incredibly tough to kill by normal means, he can one or two shot your entire force, so plan in advance. He will poison the ground, covering an area large enough to affect your group. Supply packs abound this area, so resupply and expose them in advance with Cyrus (stealthed). This is also a good time to watch the tyrant’s tactics. This is where taking those strategic points previously will pay off, so equip those rosarius items. Use Angelos’s invincibility, increased damage to target. Be ready to activate every offensive and protective capability in your arsenal and watch in amazement how quickly the tyrant’s health wanes. Once again, hold Cyrus back just in case and use his stealth revive ability. Reviving the dreadnaught can make for a great distraction when trying to extract your other forces. Retreat if you have to, but you should be able to eliminate the tyrant in one shot.