If you are going to attempt Legendary difficulty, then you wont get far without this guide. This is the place for the entire walkthrough, all missions in one place. I have done most of the missions and i have done all the harder ones, including super scarab, I also did them all solo. I will write a few levels, but it would help if we all posted in tips and guides, and i will keep it updated. There are alot of threads about different levels, i just thought we can put them all in one place.
I would not advise doing Legendary difficulty without all the skulls, but the can be done without them.
Mission 7 - Scarab
While all steps are being completed, you need to be running the warthog around the map, and using the MAC blast, destory each power core. You probly wont get all of them, but I wouldnt attack the Scarab without at least 4 destroyed. If your warthog dies, just build another one.
Step 1 - Setting up the base
As soon as the mission begins, turn on all the debuff skulls. Then start building. You will need to build, four turrets, then upgrade them with ati vehicle attatchment. Then build as many supply pads as you can, and upgrade all of them. Now this is the plan. Send Fordge to the back of your base, away from harm. Then Bunker in the two Rhino's at the left side of your base, this is used to defend the locust and hunter attacks. Then place the scorpion and ODST between the Rhino's. With this defense the base can take care of its self, there is no need for extra defense.
Step 2 - Building up a force
Now what you need to do is upgrade your reactor. Now buy every upgrade for the Cobra. The Cobra is going to be the only vehicle you need to build. Just keep building as many as your resources will allow.
Step 3 - Attack!
Now take about 3-4 of them and wait for the search light to reach the middle of the map. When it is at the middle, charge towards the Scarab with the cobras. Making sure you are going to opposite way to the scarab. If you destroyed 4 power cores, then you will easily make it to the scarb without the light finding you, so long as you go the opposite way it is searching. When you arrive at the locust bunker all 4 down on the opposite side to the scarab. But it is important that you bunker them in a line going around the scarab, and not away from the scarab. This is because the search light finds an enemy and has to charge up. If they were in a line going away, it would destory all of them in one attack. But if they are in a line going around it, then it will have to changre up on each one, and this will buy you time.
Step 4 - Repeat
Once you have all 4 bunkerd down next to the scarb, go back to your base. Get another 3-4 and go again on the opther side. If you time it well and use a bit of Micro, then as soon as one gruop dies, youll have the second group attacking the other side. repeat this a few times and the scarb will eaily die. Youll also have plenty of time, dont worry about the scarab destorying your base.
Step 5- Victory dance!
Parade around your room, cheering "Woooo! destoryed it, Yer, im sooo good"
Tips -
Use the heal power to repair turrets and units in your base for defense. Do not ever use it on the Cobras.
Always use Mac blast on the Scarab when ever you can.
Good luck!
1v1 - 48
2v2 - 50
3v3 - 47
Best player evar!!!1!