Two extra cards, four times the trouble
Deal a player four hole cards instead of two and everything downstream changes. The frame is familiar — four betting rounds, five community cards, the very same hand rankings — but now you must build your hand from exactly two of your four cards plus three from the board. Six two-card combinations hide inside every starting hand, so everyone flops big draws, monster hands run into even bigger ones, and pots swell fast. Hold'em waits for the right spot; Omaha manufactures three of them a hand and dares you to pick.