I refunded the game (it isnt bad, although the Autumn sale came right after I purchased and I wanted a game my friends bought), and the game doesn't appear to check for game ownership. I can't access Multiplayer, but I can still access singleplayer and the mission editor. I dont know if its a future plan, but probably should add at least a generic Steam check and close the game if it fails. Not a programmer though, not sure on the difficulty in adding it (may not technically be a bug, but may be of interest)
#Add check for game ownership
dawn ember
granite rapids
This is not worth the effort, bypassing basic steam DRM is little effort.