I'm trying to extract the game and install it but the application is apparently claiming to be 1 quadrillion KB and can't be extracted. What am I missing here?

I tried redownloading the file but its still not letting me extract the files and install because it's 4.5 Ecta Bytes which, again, seems impossible. How could that be compressed down to 10gigs?

Hey, sorry about the late reply! 
The file should be 6.75 Gb total.
My Google Drive says it's 7Gig, which I think is rounded up.
Anyway, I'm not sure what the issue is either.

What I can offer is trying to download the version from here:

https://joure.itch.io/stardropfirstcontact

I use 7Zip for my zipping needs (this is a regular zip, so it should work fine)
I'm wondering maybe your HDD could possibly be faulty? (I sure hope not)

I also unzipped the ZIP file I used to upload in a different folder (copy/pasted it) and that worked fine as well.
Anyway, try the file from the first contact version, it's the same experience just offered up at a different way.

Let me know if any of this was helpful!
And thank you for sharing,

I'll now download the file myself and see what happens on my end!
Sorry about the issue!!!

UPDATE: I just downloaded the demo zip file from Itch.io itself just to make sure the file wasn't corrupted or anything and extracting went without a hitch (using 7zip).

Ok that's really weird because the download is saying 9.8gigs when I download straight from Itch. I'm going to try downloading it again right now, and using 7zip. If that doesn't work I'll throw up some screenshots so you can see what I'm talking about.

Ok, 7zip seems to have solved it. Thanks!

I'm glad it did! Sorry about the issue, I'm not sure why 7zip solved since it's supposed to be a standard zip file.7zip has it's own, stronger zip format that generally yields much better results but I didn't use it for compatibility issues (most people I assume don't have it and it's annoying to have to get another app to unzip it)

So yeah, bit perplexed and will monitor if others run into being able to unzip.
That said, I'm happy it's solved for you and can only (hope) wish you'll have a good time!