Key Hunters is an easy-to-play card game designed by Caleb Mahn where the 2-6 players are trying to be the one who removes the final lock from a treasure chest. It's played with a deck of 33 cards, sporting art by Jaz Lin, but gameplay resembles that of a smaller deck microgame like Love Letter (AEG): players start off with a hand of two cards and their turn consists of drawing a card and playing a card.
You set up the game by placing the Treasure Chest card in the centre of the table with the supplied 10-sided die at position 10 on top. The die represents the number of locks on the chest, so you'll be reducing the number on the die as locks are removed (or increasing it if any are later added). To win, you need to be the player who reduces the die below 1.
The cards all designate various different actions but around two thirds of them subtract one or more locks. There are additionally cards that add a lock and cards that, for example, force the next player to miss a turn or require a player to dump their hand and draw fresh cards. As you might guess, this 'pass the parcel' type countdown game is all about having the right cards when the die has counted down to a low number. There's a push-your-luck element here too: if you play a remove one lock card that takes the die value down to 4, you might think you are safe but the next player might be holding the 'Stick of TNT' card that subtracts one lock and lets you play another card. If that other card is 'A Ring of Keys' (subtract three locks), then your opponent will have won... These two cards are especially powerful, so if you think an opponent is holding one or both of them, then that would be a good time to brandish 'A Whip' card to force them to discard their hand. In any event, this is a game where the first few turns are more about trying to collect and hold the most useful end-game cards because the game hots up as the die counts down closer to zero.
Key Hunters is a light game that typically takes less than 10 minutes. Player count doesn't materially affect playing time. You can speed up play still further tho' by playing a variant where instead of setting the die initially at 10, you roll it to determine the maximum number of locks on the Treasure Chest... The rules also suggest an option where players have a maximum hand size of two cards rather than three (ie: you hold one card, draw a card and play a card). And to keep things interesting and add more of a chaotic party game feel to Key Hunters, the rules suggest alternative uses for various of the card types; for example, switching hands with a player when you play a 'Tall Trap' (miss a turn) card on them.
This isn't a game to take too seriously but Key Hunters is a small tuckbox game that you can carry around in your pocket and which can make for an entertaining filler.