The goal in Chronicle: Runescape Legends is to win matches by reducing the Health of your opponent's Legend to 0 or less, thereby killing them, before your Legend's Health falls to 0 or less and dies. The opponent (called the "Rival") may be either a computer player (in "Solo Play" mode) or a human player (in "Play" mode). Playing the game consists of dragging Cards from your hand onto "Slots". Cards do things like give your Legend Gold, Armor, and Weapons, and damaging the enemy Legend. The two main types of Cards are Support Cards and Creature Cards.
Each match lasts up to 5 turns, and both players play simultaneously during each turn. These turns are called "Chapters", and each Chapter has 3-4 Slots. Not all Slots must be filled to complete a Chapter. In fact, it is legal to leave all Slots empty, although it is usually good strategy to fill as many Slots as possible. If both Legends are still alive after at the end of the 5th Chapter, they battle until one of them dies.
During a given Chapter, after one player finishes placing cards and clicks the button to indicate that they are done, a timer starts (indicated by a burning fuse on the button) and the other player must finish placing cards and click the button before the timer runs out. Otherwise, when time runs out, play proceeds as though the timed-out player had clicked the button at the last second. Regardless, after the card-placing phase, both Legends will walk to the Slots in order and interact with the Cards placed there.
In the case of Creature Cards, Legends interact by battling the Creature, whose Attack and Health are on the top of the Card, and whose rewards (Gold, Armor, a Weapon, or a permanent Attack boost) are on the bottom of the Card. In the case of Support Cards, Legends interact by paying the Gold cost on the top of Card and gaining the rewards listed on the bottom of the card. Many Cards also have text which describes additional effects which occur after killing the Creature (if a Creature Card) or paying the gold cost (if a Support Card). This "card text" may also contain Keywords in order to keep the description short.
The goal between matches is to acquire more Cards in your "Collection" which can be put into your Decks. Before each game, you select a Deck to use. In each game, you only draw cards which are in your Deck.
The game has three primary currencies which are used to acquire Cards. Copper Coins are earning in-game through various means, but mainly by completely Daily Quests. Gem Shards can also be earned in-game through various means, but mainly by destroying unwanted Cards in your Collection. Platinum Ingots are purchased using real money.
Another valuable outside-of-match resource is Experience, which is used to Level up your Legends, thereby gaining Cards or other resources. You don't "spend" Experience, in the sense that you have no control over the rewards for levelling up.