Yeah, I can definitely see it being a horror movie and it would be relatively easy I think.
Make it Uno, but the game that they play in the movie is the original game that the popular version is based on - kind of a Grimms' Fairy Tale type situation. The decks are haunted and everyone that plays is cursed and have to get rid of all their cards in like 24 hours or they die. But they can't just like throw them all away, they have to play them/use them somehow.
But yes, they have to say "Uno" or they die immediately lol.