Halls of Hegra

From Trompet Games:

Play as the commander of the Norwegian forces. Explore the fortress and dig your way through mountains of snow and broken equipment. New recruits are joining while you plan supply routes for the coming siege.
Defend the village below the fortress while you do the final preparations before the Siege. Send out patrols behind enemy lines to secure enough supplies.
During the Siege you have to endure constant bombing and infantry attack while keeping the morale up amongst your men. Will you survive?

Halls of Hegra is a solo only game where you play as the Commander during the siege, which is divided into three stages. The mechanisms you will use are worker placement, bag building, and area conbtrole / tower defence.