A 1-4 player co-op PC game in which teams deliver parcels for the Pan-Galactic Postal Service. Due to a galaxy-spanning outbreak of interdimensional monsters, all cities are on lockdown. But that won't stop your team of parcel carriers from locating the delivery addresses for every parcel in their care, nor will it keep them from braving toxic obstacles and waves of ambulatory brain creatures in their quest to get every precious delivery to its destination! As teams log successful delivery runs, they accrue payments that can be spent in the postal supplies shop for new items to help them take on new challenges!

Mailstrom takes place in a far future where interstellar travel is routine, and the shipment of goods to private addresses is handled by the Pan-Galactic Postal Service. The PGPS is a quasi-government entity, overseen by the Galactic Hegemony. As Plasm outbreaks have forced many cities into lockdown, the PGPS has chosen to classify parcel carriers as essential workers, and has prioritized the prompt delivery of mail over outdated regulations pertaining to workplace safety.