Skyjo Action adds (as the name suggests) Action Cards, which allow for special moves: Exchange cards in your tableu, Exchange cards between players, Steal an action card, Take two turns in a row etc. You get an action card whenever you put or reveal a Joker in your tableau, or you can take an Action Card instead of a normal move. Jokers allow for easier set collection and make very valuable sets in themselves (-10 or -15 points).
As a new rule, rows of identical cards are now also discarded.