From the product blurb:
Shelter is a game of survival in a war torn city, you must build your shelter, gather food and water, whilst avoiding the daily threats the war has created. The game has rules for you to play in a fantasy city under siege, a modern city caught in the crossfire or a future city under alien occupation.
Rules for building equipment and trading, gathering resources and other survivors, protecting the shelter when your away and for finding larger shelters to hold more people and stuff. You can play to survive or to take from others.
For those who loved This War of Mine and the Powered by the Apocalypse rules, Shelter is designed for oneshots or short campaigns. The book comes with a number of encounter tables and treasure tables for each of the 3 city settings within, rules for magic and disease, starvation and thirst.
This has natural applications for Traveller conflicts, especially for civilian PCs caught at the wrong place at the wrong time.
The magic rules may be amendable to a psionic rewrite, especially if psionic power can be generated eletro-mechanically in your universe.
Even if it can’t be, they might still be useful if you think the Zhodani (say) have found rare
magical psionic objects or beings (animal or sophont, or long-lost Ancient of Droyne technology) that can be used to magnify their brainwaves and power. It’s a big universe, and there’s a lot of worlds in the Zhodani Consulate that have never been visited by an Imperial…