I just finished the second season of Silo.
Overall, I enjoyed it, but the whole season felt like one long delay. You have the main character completely isolated in a side story. There was a bit of interesting stuff, but it mostly just ended up taking 10 episodes to get back to the main plot.
As for the plot in the Silo itself, again, it felt like things were being strung along to get to the point where they would meet up with the main character again. You knew it was heading for a war, but you also knew that things weren’t really going to take off until the main character can come it at the last minute to stop things. It just felt a bit predictable.
In some sense, it fleshed out some of the secondary characters a bit more. Although, I can’t say I’m particularly interested in any of them. Most of the engineer characters seemed forgettable, and probably the only two secondary characters that felt interesting were the sheriff and Lukas doing the decoding. I think the show suffers from not having any villains that feel compelling.