Gunhound EX had Steam trading card support added on 1 May 2014. There are 8 cards in the series, and you'll receive 4 cards at random for purchasing and playing the game.
Note: Cards #1 and #7 had the same name with a different visual. Someday, the name of card #7 was changed from 'Juliane Juri' to 'Juliane - Pilot' to remove the confusion. The previous visual is visible here : Juliane Yuri.