In ONDA, players dive into a card challenge where the goal is to form superior sequences to their opponents, always keeping an eye on the tide! The main trick is to be the first to get rid of all your cards; if you can't, the ideal is to have as few as possible, as each card remaining in hand means negative points.

At the start of each round, the tide is coming in, meaning higher-value cards are the stars of the show. Each player starts with a handful of cards and chooses two to place face down in front of them – these are their wild cards and still count as part of their hand. The lead player opens the trick with a formation: it can be a single card, 2 to 4 cards of the same value, or a sequence of 2 to 4 cards. Subsequent players have several options: play an even better formation (always following the tide's flow), pass their turn and be out of that trick, or, the most strategic move, turn the tide! To do this, you take one of your face-down cards back into your hand, flip the tide card (now low numbers are best, or vice versa), and then play a superior combination. Oh, and there are bombs! There are six types of bombs in ONDA, and the current bomb is always visible. A bomb, like a two-card sequence of the same suit, supersedes the current formation, and players must beat it. But beware: only one bomb can be played per trick, and only one player can turn the tide.

When all but one player have passed, the played cards are cleared, and the top bomb card goes to the bottom of that deck. Whoever played last leads a new formation. The round ends as soon as a player has no cards in hand (ignoring face-down cards on the table), and everyone else loses points based on their unplayed cards. After four rounds, whoever has the most points is the big winner of the sea!