While exploring and blasting your way through Griftlands, you have a variety of unique cards that you use in different situations from two decks, your negotiation deck, and your battle deck. You can upgrade these cards in each deck and eventually upgrade them to a better version of the normal card. The traditional way is to use them enough times during encounters, but you can find random events in the game where you can choose to upgrade a card from one of these decks.
Most of your cards in your negotiation and battle decks should have a small bar at the top, indicating how many experience points they need before leveling up. You gain experience points with these cards by using them in encounters. The experience points you gain after each use of the card carry over into other battles until you use them enough times that you have the opportunity to upgrade them.
Experience point requirements vary for your cards. Some may only require three uses, while others may require seven. You can inspect a card by looking at your decks at the top right of your screen and study the different leveling options, or you can do so while you are using your deck. 'an encounter.
An alternate method of improving a card comes from a random event. The type of events vary and occur when you walk to a location on the map. During the event, you will have a list of options to choose from on your screen. Before selecting a choice on how to react, you can see the result and what the results will be before accepting it. If you see an option to upgrade a card in your trading or combat deck, choose it to automatically upgrade one of the cards held in your deck.
The upgraded map will remain on your character for the rest of your run. However, if your character dies, you will lose all experience points on a card and start over.