Halo Wars

It should be noted that despite what the description says, you can't simply put all of the Colonies into Hibernation at the same time and get the achievement. Instead, you actually have to put all of the Colonies into Hibernation at the same time AND kill the big "boss" at the end of the level (they refer to it as a "large creature" during the course of the mission, but it looks more like a big, bubbly building to me). Let me say it one more time: If one of the Colonies comes out of Hibernation while you're battling the final Flood boss, no achievement for you!

That said, your Hornets will be your best friends in this task, as the first Colony you destroy is certain to regenerate by the time you've made it to the last one. I built up about 10 or so Hornets and worked my way from Colony to Colony, and whenever one regenerated (which seems to happen after a few minutes of gameplay), I simply zipped my planes back and destroyed it before moving on.

After all the Colonies and the big dude are dead, a movie will play and the achievement will pop up!

This achievement is actually very easy when you try. All you need to do is make your entire army fully-upgraded hornets. Once you have the maximum number of hornets, send them over to each colony while upgrading your carpet bomb. Once you down a colony, leave 1-2 hornets there, rescue the Spartans and down the last one near them. Now, all you have to do is kill the large creature, but luckily, it is lit up. With the colonies you have destroyed, the large creature's heath should be very low, and sending a large or medium carpet bomb in there will destroy it once and for all. Now just wait until after the cut scene and you'll have your achievement!

You should just make 5 warthogs 3 hornets and the rest scorpions first go to the colony ahead of you and destroy it then leave sargant forge at that base then have them go to the one next to the spartans and destroy it then leave all your marines there go then send your hornets to the one at the right of your base and leave them there go kill the ones next to the big boss but don't leave anybody there and then have all of your units not at other colonies attack the boss and carpet bomb it then you'll have your 5G achievement =)
heres a video i found useful

This one was very easy. Just steadily build up your base so you have a good fast supply of resources coming in, and then build hornets.

Lots of hornets.

Upgrade them to Hawks, and then you should be able to sweep through and kill every colony in a matter of a few seconds, making the final Proto-Gravemind a simple kill.

If you would like, upgrade your carpet bomb in order to kill the Proto-Gravemind in one shot.

There are 5 total flood colonies. Explore the map between you and the Proto-Gravemind to find the first 3. The other 2 are right next to the Proto-Gravemind.

What you need to do is first destroy 1 elephant. That done, you need to upgrade warthogs and hornets to maximum ability. Then send 1 warthog to the spartans. Recover them and send them to the empty base site. Make a base there, and scount the whole map with 1 warthog, but make sure it's dead before you begin. Now upgrade carpet bombs to max.

Carpet bomb the main creature until it has low hp. If it's not low enough (in the red) send 1 warthog to lower it, and repeat until it is in the red hp. Then make as many hornets as possible.

One it is, send the spartans from the newer base to the flood base just east of it. Kill it, and them send 1 hornet to the flood base south of the newer base. Once it gets there, carpet bomb it. Then send teams of 3 or 4 hornets to each of the other flood bases, but a few more to the one right in front of the creature.

Once it pops up saying the flood bases are dormant, select all units and attack the main boss that should have low health. Carpet bomb if possible. Once it's dead, you'll get the achievement.

Gratz!

If you haven't run through the entirety of the campaign to get find all the skulls then this is my solution to you! This is a 0 skull, EASY difficulty, and about less than 30min run for me.

You can take as much time on this level as there is no timed-objectives on it. There are 2 bases you can have on this level. The initial base is where you will set up everything essentially, the 2nd base is only if you want to utilize making more Hornets (only if any get destroyed since its closer to the boss and 2 of the Colonies). The 2nd base is found in the very North-East of the first base (if you go from the center of the 1st base and drag your reticle up north you'll see a crashed pelican and then go east and you'll find the 2nd base).

Location of Colonies:
- The game will Ping the locations of all 5 Colonies after damaging the first one ONCE, but they are the big red circles on the map.
- It will Ping the location of the Colony that is regenerating.
- All colonies must be dormant (aka hibernating) before you defeat the Boss for it to count!
- It will warn you WHEN and WHICH Colony is regenerating so you must pay attention for those pings.

Base Supply & Defense Set-Up


Hornet Location Set-Up


TLDR