Take a look at what's registered on Steam: http://steamdb.info/search/?q=strike+suit+zero&type=

Marauder Strike Suit
Weapons pack
Heroes of the Fleet
Raptor
Korean version
Mod tool

Hopefully GOG will get the DLC system implemented soon, and I might even consider getting the lifetime DLC upgrade.

I bought the game just in time to get the special promotion of free dlc :D

Update: Raptor is available for purchase, and Marauder is in beta testing (or released already, who knows). Mod tool released just today.