Puzzlecards presents you with a 4x4 grid of cards, each bearing a number and a symbol. To advance the the game, you must slide two cards of the same value into each other. For example, two "1" cards become a "2" card, two "2's" become a three and so on. Eventually you progress through the face cards and combine two kings, the game's ultimate goal. It's a fun, waiting-in-line-at-the-DMV game and as I said, it's already been done.
I understand that everything is a remix, but Puzzlecards doesn't offer anything that differentiates it from those other apps in a significant way. If you haven't played Threes or 2048, or if you can't get enough of that type of game, give Puzzlecards a try. It is free, and an optional in-app purchase eliminates ads, allows you to pick a new card to add to the grid, and enables an alternate dark theme.