The sets are cross-compatible – cards from multiple licenses can be included in the same deck, and characters from different universes may face each other in a match.
The character determines a player's hand size, starting vitality, and each has unique abilities for a deck to make use of.
Also unlike other CCGs, the cost to play a card in UFS is not a set number of some resource.
Due to the large number of cards drawn and played, (nearly all of which have an ability or two) the risk-reward nature of the control check system, and the importance of guessing at and playing around the opponent's hand, UFS is generally considered to be one of the more complex and skill-intensive CCGs currently active.
There are five different card types in UFS, indicated by the color of their border and other traits: In 2008, Scott Jon Siegel reviewed the game for Engadget, noting that his "play experience with the game was not the most positive one", but stressing the subjectivity of his opinion.
The reviewer of the latter noted that "Once you slog your way through the rules, UFS can offer highly strategic and intriguing gameplay.
"[4][5] In 2024 the Attack On Titan-themed expansion was reviewed for the Comic Book Resources by Jenny Melzer, who gave the game 8/10, praising its artwork and multi-franchise nature, but criticizing the complexity of the rules.