This, in my opinion, is a stunning first chapter. Very well executed and the first line just reeks of lore and depth that draws the readers right in. I dig the letter format so much, since it is akin to some of the best creepypastas out there- and as to segway into a question: do you read creepypastas?
This is the first story on fictionpress that I am genuinely excited for the next chapter. The premise is so interesting. Good job!

Okay, this was a fairly interesting and informative chapter. However, a few issues. Presuming these are aliens, the term "superhuman" used here seems a bit out of place. Even a humanoid alien probably uses different units than Earth's metric system. Likewise, if the Biomass relies on conventional wave assaults and swarm attacks (a highly effective form of offense in nature), might it also use swarms of smaller flying insect like creatures as scouts or early stage vectors? Infecting targets behind enemy lines would be a great morale killer for soldiers.

Okay, I am liking the whole "Galactic War Z" approach, as it's an underutilized one in sci-fi. This would be a great roleplaying setting or World War Z type project, as there's very little in recurring cast (at least so far). Still, there's a few issues.

For one, the log of the combat droid. There was very little military terminology or tactical discussion (from the point of view of the droids, at least). It is refreshing to see the biomass creatures using actual tactics and adapting, though. I had a similar idea for an older story of my own. What kind of units engage the biomass? What formations? I imagine the droid the log came from was some type of light infantry, given they had a close combat loadout and frequent encounters at close range. Do the droids have analogs of suppressive fire weapons (energy or projectile)? Aside from blades and energy weapons, how about analogs of artillery, sharpshooters (especially those with anti-materiel munitions and weapons), suppressive fire, and demolitions? Likewise, the droids may not have sentience (or so the general thinks), but there's frequent use of first person terms (although that could be the general being an idiot). You mention more military hardware used in chapter 4 like nukes and cruise missiles, but there's little detail of potentially more advanced weapons the aliens could deploy, despite the fact the droids brought out energy weapons. Still, will continue going on.

Okay, a few pointers here. For one, a bioweapon able to outcompete much of the life on Earth (as well as potentially aliens that evolved outside Terran conditions) would pose little threat to outer space, even if chunks of the planet got blasted upwards, as gravity would pull them down. Check out a volcanic phenomena called a Verneshot, which has happened before and is orders of magnitude more powerful than a combined nuclear detonation. But as far as something spreading around the Earth, I've seen the concept done really well in Peter Watts' "Rifters" trilogy. I highly recommend reading that.

I live in the UK and I don't really like the diction that you use in your stories.

liking it judging by the opening, I'm writing a zombie story too and there my favourite genre so they always draw me into reading.
Liking the descriptions so far as well, somehow I think this going to turn into a "Dead Space" kind of story.

An interesting account of a galactic crisis. You've managed to capture my attention with the information given about the biomass and the fight against it. I should hope that some enterprising individual does find an effective method of dealing with it in future.

-Having never been in love before, I couldn't tell if this cycle of coldness and then warmth was normal, or if we were just mad like that.

good very add some dialog, make longer. pull more weeds

if no star then how solar panels work