TimVic
im still gonna read this novel because its written beautifully and thought out well but just gotta say my own preference is i hate shop systems just for me never fits in with the story or world and kinda ruins it in my opinion if you can get this shop system done good then well done really cause ive never seen a good shop system that fits in.
Just had to re-read some previous points but from what you typed, Gustav got the system upgrade feature about 4/5 days ago starting from after he got shot with the energy on the ship. From there 1 night passed and the next day was the knowledge exchange and 2nd day was the fight the 3rd day I believe they returned home so even if it wasn't done upgrading, it would be way more than 34%. Another thing was the system activated to steal Zim's bloodline but it didn't active to take the worm bloodline? And then of course he waited an additional 2 days for it to upgrade? You could probably just change the days required for the upgrade since it isn't a major thing but the bloodline absortion thing seems kinda big. If i'm wrong about this sorry but good story nonetheless :)