Rival Megagun is already available via digital download, and its success there is allowing it to make the jump to selling physical versions; and with a physical release comes physical release goodies! Set for June delivery, the physical release is limited to PS4 and Switch. There will be two versions of the release, both will include the game, 60+ page manual, and sleeve packaging with internal art. The Collector's Edition nets you the above, plus a tournament board game in-game trading card replicas, hardcover artbook, CD soundtrack, and additional materials like a wall poster and alternate cover sheets.
This physical run is a limited event, with 3000 Regular Edition copies for Switch and 1500 Collector Editions; 2000 PS4 Regular Editions and 500 PS4 Collector Editions. Every physical copy will also receive a collector coin with the unique production number of each game.
Rival Megagun is available digitally via Steam, the PSN, or Nintendo eShop, but to get the physical version you will have to head over to the publisher's site: https://firstpressgames.com/collections/rival-megagun