Narration:With Arm presence, once again firmly (...) on Thalassean, the commander began dispatching scouting teams in search for further objectives. They were successful - a squad of P.T. boats discovered energy patterns, matching those of the Core galactic gate, emanating from one of the northern islands. The island was heavily guarded - it would not be taken easily...
Capture the Galactic Gate.
*Special Priority 1A Prime* A squad of Skeeter scout boats has found a heavily guarded island to the north. Energy emission levels indicate that it may be the site of a Core Galactic Gate. Find that Gate and capture it. By doing so you will secure Thalassean for Arm! ...and open the door to another Core world.
Info Feed Immediate construction of a secure base is critical. Core will not relinquish the gate without a fight! Be careful not to destroy the Gate with offshore bombardments!
Starting units: Commander, Shipyard, Jethros, Hammers, Lurkers, Skeeters, Crusader, Ranger
The Arm Commander starts with a small naval base on the southern island. Immediately set the Shipyard to build a Construction Ship, followed by a series of Lurkers. Set the Commander to secure resources, followed by a Vehicle Plant. Produce Samsons to prepare for a Core air assault. Arrange naval units to defend the Shipyard, and set the Construction Ship to build Torpedo Launchers to do the same. Once initial defenses are secured with vehicles and ships, build a Construction Vehicle to start producing defensive structures around the island.
As the units become available, push the defensive lines out towards the nearby islands. Defend the channels between the islands well, and keep ships with longer ranged weapons in the open sea behind the front line defenses (don't forget to keep subs in the channels and patrolling the open area between the islands and your base). Get the Commander over to the small island northwest of your base and build a Radar Tower. Set the COnstruction Ship to build an Advanced Shipyard near the original Shipyard. Keep the first Shipyard building defensive units, but throw in a couple of transports for later use.
When the Advanced Shipyard is ready, set it to build Piranha, Rangers, and Conquerors in preparation to begin an assault on the center island. Expansion on this mission can be very slow, getting from the beginning of the mission to the point where you can safely occupy the center island could take two or three hours of production and slow movement of defensive lines forward against the Core. Build a Guardian on the island just northeast of where your Radar Tower should now be sitting. This should help to soften up the center island along with the long range weapons available in your naval fleet.
When you're ready to start the real assault on the central island, load up the transports you built earlier with some Jethros and Samsons. Make sure you have a large group of naval units, and soften the island up for a while with the Guardian and the naval units' guns. The transports should be staged to allow the units to prevent enemy aircraft from doing significant damage to your fleet, and remember to patrol around the fleet with subs to prevent a dangerous undersea attack. Clear the island and secure it and the smaller islands nearby.
It may help to build an Advanced Vehicle Plant to produce amphibious units for the final assault while securing the center island as an assault base. When things are fairly secure, stage the Commander on the center island to wait for a clear path to the Gate (be careful not to destroy the Gate trying to make the way safe, though). It may be useful to build another Guardian on this island, but just like the guns of the ships you'll have to be careful with targeting. If you built some amphibious vehicles, send them over ahead of the Commander to do the last stage cleanup (or earlier if it seems they can help), and let the Commander clean up the last couple of units that may not come away from the Gate. Capture the Gate and the mission is over.