I recently did this on normal. At first the mission is quite daunting because of the amount of stuff coming at you. But the broad strategy the briefing gives is pretty valid. Survive until you can finish DRP, and killing shoguns early on is key. The detriments throw quite a curveball in there but they are totally stoppable.
I grinded pretty hard to get all bonus objectives on this one, and by the end had a pretty reliable strat to deal with everything that would get thrown at me on time. It ended up being quite turtle-y.
At the start of this I would take the 3 free conches and make the anti-nuke, usually a little south of the DRP, they were on high priority during this. I found 2 anti-nukes for total coverage of all my land wasn't worth it. You need this finished before 4 minutes or you are going to be real crispy.
Commander dropped an air factory. Air factory would make 10 cranes, unassisted by the free caretakers you start with. They'll be mostly done by the time you need them. These heroes are going to kill the detriments.
The 2 shipyards would go on repeat, making seawolves. Their job will be to buy the cranes time.
Quickly, you tell the conches doing the anti-nuke to wall up the beach at the north-west, and the commander the same but the beach at the south-east. At this point, the only things that can get in anywhere but your front door are amph-bots, who will hit the south beach, and the 2 detriments.
The commander should drop some anti-raider defence, I would usually do a little line of pickets, queued up after the wall. You also want to get anti-air back there. Razors and chainsaws are good for this. Gunships will attack the mexes and fusion reactors after about 6-7 mins. They attack the north beach with hovercraft, the wall from the conches is enough to stop that completely, like the chronolegionaire says: Never existed.
With those orders set up you can take the seawolves hunting on each side of the map. You want to get started at least by a minute in. The orders set up already can play out while you focus on the task. Take out every envoy, reef, and shogun you can find. Ignore sirens, they will patrol around, so you don't need to fight them for access to the capital ships. When you start running out of targets go for the 2 shipyards and strider hub on the coast. The strider hub is just north of the shallows connecting their land to yours. A shipyard is a little north/west of that. The other shipyards on the coast a little south of the shallows bridge.
The main thing is to get the reefs, shoguns and envoys, but if you stop them producing more for a while it will get real comfy. You will lose everything at sea, for a while. There is little you can do to stop it, there are a lot of sirens you aren't ready to take on at the start, if you want to retain the sea.
Using the cranes and your conches (they've probably finished the wall by now) the front beach is reinforced with a single cerberus, many area shields and some lucifers. 1 cerberus will ward off the sirens and push them away and let you get the rest up. Put it far enough back that it doesn't just get nuked by sirens, and far enough forward that it will cover a bunch of sea.
Detriment number 1 is going to walk in the front door at about 9-10 minutes. You want several big boy towers under too many shields as you can get when they arrive. I usually managed 4 of them and about 12-18 shields. DRP should have finished up around now too. Detriment should get try killing one of your towers, shredding through bubbles, but there are too many. By the time it does a little damage it gets scared and run away with you only losing maybe 1 tower. DRP can finish it off at sea.
After this happens, your mission is to negate detriment number 2. This one will almost always walk at your south east beach and your fusion reactors. You cannot stop them, they WILL get back there. Then they'll go walkies around to your singularity reactor. I tried so many little mazes of walls to coerce it to the front, but it is very determined. Another set of endgame towers can be built in the 5 or so minutes you have to prepare for this. Make a few fusion reactors out back to prop up the grid just in case.
Once they're both dead, spot targets for DRP with owls and sparrows, and push forces out. If you take out the anti-nukes trinity can make short work of large sections of the huge base on the other island. I opted for a large force of phoenix bombers.
DRP can delete anything you point it at, across the map. Find the factories and reactors and you're done. I managed the bonus objectives with this strat. Not the only way to do it, but I am bad and needed a really safe plan. If you aren't going for all bonus objectives you can take your sweet time doing the rest.
The last 3 super weapon missions are all kind of like this. They have their own little set of problems to overcome right at the start and then it is smooth sailing as you annihilate them with the superweapon. I'm not as confident about the strats I used to beat those, but they were less rigid than my strat ended up being for this map. If you can't tell, I have this map seared into my damn brain.
