man, I haven't played a doom game since the II came out a bajillion years ago.
...but I can't do first person stuff very often anymore so I'd be worried I probably wouldn't be able to play it.
Basically you are going through rooms on a map as an adventurer guy and using attack/defend cards to fight the monsters. There's a big boss monster at the end of each floor. If you beat all three floors, you win.
It's not a card game like Hearthstone/mtg/whatever. There's no persistent deck building or anything, you just pick up new cards during the game. The cards are just the combat mechanism.