Balatro · system clarity
A small rule set, a large combination space
Balatro is a PC card game built around poker-inspired roguelike runs, and it is one of the clearest current examples of a rules-light indie hit. The system set is small. The combinations are not.
That gap — a short rule list on one side, a wide possibility space on the other — is what produces replay value without a content mountain. A studio building a metroidvania or a tactics game can borrow the principle without borrowing the genre: define the smallest set of rules that produces interesting decisions, and let the combinations carry the hours.