Why has nobody done this before? The moment I type this I start to suspect that maybe they have. Wasn't there an early card-based entry in the Apple Arcade line-up that did something similar? Wasn't there a...
It doesn't matter. Someone's done it now and with real class and atmosphere. This is Bardcard. Remember that game where you put a bunch of cards face-down in a grid and you turn them over two at a time looking for the pairs? Bardcard uses that game - the bored bank holiday game, the Mario 3 game - as the engine for a roguelike. And it works as well as you might imagine.
So you have health and energy. Health goes down when you take a hit in combat. Energy goes down as you turn over cards. Each level of the dungeon here is an arrangement of these cards, face down. Start turning them over in pairs. Two coins? That's money in the bank. Two wearables? That's a new piece of armour to equip. Two piles of rubble? Want to hunt through it? You might find something cool in there.
Two bats? Time to fight! Turn-based fights in which you use equipped weapons and read enemy tells in order to know when to block. Bats, rats, all kinds of horrors. Keep going! Get the battle out of the way and then get back to turning over those cards.
Eventually you'll turn over two character cards, which means you might get a choice, or a shop, or a piece of the unfolding plot. After that maybe you'll turn over two staircase cards, which means you get to go down to the next level, where the whole thing repeats, but harder.
All good - and of course the real fun of the game is when you turn over cards but don't get matches. So you have to remember where everything is as your energy goes down. Bat here, where's the other bat? Where's the other coin?
Here's the thing: there's a real trend these days in taking roguelikes and shoving something else into them, and this particular card game is ideal for that. It's ideal I think because it provides the randomness and the drama, but it's also simple and easy to get your head around and it gets out of the way because you know it already. It's randomness and surprises, but it's also only lightly taxing, and it allows you to play your mind across the whole surface of the game, not just this part. Clever, I reckon. And I reckon Bardcard is pretty much brilliant.