Like Coins and Bombs, you can carry up to 99 keys at a time, and any additional keys collected will not be counted.
Keys in shops cost 5 coins, 3 when on sale.
Usage for Keys
Contains two free book Items (Such as Anarchist's Cookbook, Book Of Sin, Book Of Belial, etc.) on two pedestals inside. The door is identical to that of a Shop, but is marked with a book on the mini-map instead of a coin.
Drops a large amount of Pick Ups when opened, and sometimes an item, trinket or another Chest.
Blocks Isaac's movement, will consume a key and open up when walked over. Rarely drops a Pick Up when opened.
Added in Wrath of the Lamb DLC; a Golden Key has a 1/50 chance to replace a normal Key when one is dropped. When picked up, a special sound effect is played and the Key icon on the HUD gets a Golden Key next to it.
When Golden Keys are held, any object that is opened will not deplete Isaac's current supply of Keys, effectively giving him an infinite supply of Keys (except when donating to a Key Beggar). The Golden Key is removed upon going to the next floor.
Key Related Items
The Skeleton Key
Increases the chances of a Key/Golden Chest dropping after clearing a room.
Note: This item has no effect in v1.48 and above.
- Keys become much more useful when paired up with Guppy's Tail, as Golden Chests will drop more often, requiring more Keys.
- It is highly recommended that you save at least 4 Keys before going into The Chest, as all of the dropped chests require a key to open and always have an item inside.
- The sound effect for picking up a Golden Key is re-used from Super Meat Boy (another game by Edmund McMillen), albeit slowed down.