Anyway, I kinda assumed Gun was infected the moment our MC eyes turned red and their symptoms were hinted to be the same. The tentacles just confirmed it and I am now pretty sure. WE GONNA HAVE ALIEN BABIES!!! Please tell me, I'm not the only one that think that was a womb! As for the plot, it is indeed kinda simple to outline.
1. Alien race is dying, crash landed to earth
2. Infected bunch of people to find perfect host How thoug? We only knew MC was infected because he came close but how was Gunninfected.
3. Found perfect hosts, put eggs to MC and redeveloped it's body to be able to carry? maybe?
4. It chose Gun to fertilized the eggs.
5. Alien race has now evolved and has now ensured it's race survival
6. Evil person found the last cocoon of the alien race and is now using it for experiment. Of course, he wants to weaponized it. He also knows the MC has now completely evolved. You know kinda like Alice in Resident Evil Movies.
Also, this may sound out of topic but damn, the author really knows how to draw cock.