Mission: Encounter with the Gyaroxi (time related)
Details: (Gyaroxi) ssssss... we arrrre a peacefulllll race, but havvve beennnn plagued by thossse damned Drannik dronnnes. Ourrrr plannetttsss are in greattt need of help.... but we nnneeed to know that weeeeee caan trussssst you. You mussssst seeek the Drannik plague ssshhhip and dessssstroy it.
Energy: 25
XP: 55
Rank 10.
Rewards: Battle: Drannik Plague ship. (Drop: Drannik Virus. Halfs defence and attack of a planet, stops population growth. Powerful, but unique.)
Completions: 1.
Rounds: 80.
Follow up mission.

Mission: Gyaroxi Request.
Details: (Gyaroxi) Yesssss.... you havvve done yourrr job welllll, you musssst fund ssssomething that can turrrrrn waterrrr into goooooooooo.
Energy: 25
XP: 50
Rank: 10.
Rewards: Goo terraformer. (Usable on Aquatic, Terra, and Gaia planets, +2 size, -2 mining, +4 artifact, +3 research, converts to goo)
Completions: 5
Rounds: 30
Follow up mission.

Mission: Goo Conversion.
Details: (Gyaroxi) Ssssssoooo, yoooou have managed thaaaat. Nowwww you musssst take the terraforrrrrmers and converrrrt aquatic planetssss into goooo.
Energy: 55
XP: 100
Rank: 10
Rewards: Goo shifter. (Usable on Goo planets, 2 artifact, 2 research, 200 cloak, 2 space.)
Completions: 5.
Rounds: 40.
Follow Up mission.

Mission Unfriendly Locals.
Details: (Ix) What have you done you moron!? You are killing my people and allowing the Gyaroxi invaders to steal our homes! We now declare war on your entire race! We must protect ourselves!
Energy: 300
XP: 900
Rank: 50
Risks: Guaranteed return fire. (Medium Damage)
Rewards: Ix weapon (random from Laser (10 size, 40 attack) Phaser (12 size, 48 attack) and 'Cept laser (12 size, 8 attack, 40 defence.)
Completions: 5.
Rounds: 1.
Follow up mission.

The Gyaroxi Reward
Details: (Gyaroxi) Thank yooooou! You have ssssaved our homessss! We welllllcome you any time that you wisssshhhh to come to thisssss sssssacred place!
Energy: 55
XP: 100.
Rank: 100
Rewards: Gyaroxi Pact, allows you to become the Gyaroxi race. (Gyaroxi get a passive ability, that when attacked, their is a chance to lower attack or defense by 10%, activation of ability appears on news feed)

Info on races:
The Gyaroxi are a slug-like race, who thrive on Goo and Germs, they are at constant war with the Ix, for reasons no-one has ever found out It is thought that the Gyaroxi are mutated from the original slugs on a mythical planet known as Earth, but they remain mysterious.

The Ix are a race ant-like in appearance, albeit aquatic and thus, have gills. They thrive in aquatic areas, and they hate the Gyaroxi and humans, who polluted their waters many eons ago, forcing them to delve into space. These ants could be mutated from the ants that the humans used to kill, a theory based around their appearance and hatred for the humans. They are normally quite easy going, but during a war they are most formidable warriors.

EDITS:
More info added on races
Ix no longer unlockable
Reverse terraformer swapped for Ix weaponry.
'Unfriendly Locals' Story changed
'The pact' changed to 'The Gyaroxi reward'

Here is my opinion: (with the usual disclaimer that I will try to be objective and don't take what I say personally)

Plot:
The idea of space slugs is really cool.
The idea of an ant race is original.
The story progression seems similar to the Octafari chain: race was wronged and wants compensation, you help them getting something in return, they turn out to be the villains, you fight back and win.
I don't think the Xi would be that quick to ask for your help since you just worked on destroying their homes.

Description:
What is the reward for defeating the Drannik Plague ship in the first mission?
The goo terraformer could have a better name. Perhaps call it a Gyaroxi Sludge Detonator?
The details for the Goo Conversion mission describe it turning aquatic planets, yet you already describe that in the planet changing artifact.
The Goo Shifter doesn't have any background information (in the mission or by itself) that explains why it grants those stats.
Just like before, the Reverse Goo Terraformer could have a better name. Perhaps call it the Xi Wave Purifier?
There is already a Mission called The Pact I believe.
There is not much detail in who the Xi and Gyaroxi are other than their appearance.
It is not explained why the Xi have that as a racial bonus.
The Gyaroxi ability sounds similar to the Scalar Assault of the Vox (a race I made in the Zophah Saga Part 1)

Technical:
The idea of turning planets to goo is cool, though I would limit it to only oceanic planets.
Also I think it should not be that powerful. I suggest +1 size, -2 mining, +3 artifact, +3 research.
Having a mission unlock 2 new races at the same time appears a bit unbalanced.
The Goo Shifter has very similar stats to Octafari Grid Pylons.
The idea of turning a planet back from a special type would not increase the stats further, and would diminish the value of it being unique from other planets.

And again,

Thanks for the feedback, I will consider the similarities and overpoweredness of the unlocking 2 races. I haven't seen your Zophah saga, so sorry if it's a bit similar I shall also add more detail on the 2 races. I'm currently trying to fully complete the octafari chain, so it makes sence some of it might be based around it, as I spend most of my time on GL looking at those screens. I shall review it.
Oh, and its 'Ix' not 'Xi'. lol