Sushi Go!

Each round everyone secretly chooses one card from their hand (face-down) and then all players reveal simultaneously; after revealing, pass the remaining hands to the left (standard) and repeat until hands are empty (Rulebook, p.4; summary list, p.12).

A wasabi triples the score of one subsequent nigiri only — you may place a single nigiri on a wasabi to get triple value (one nigiri per wasabi) (Rulebook, p.5; nigiri/wasabi scoring, p.9).

When you play Chopsticks you may later use it instead of taking one card to take two cards from your hand (announce 'Sushi Go!'), then return the Chopsticks card to your played area (Rulebook, p.6).

Count maki icons; the player with the most maki gets 6 points and the second-most 3 points; if players tie they split the combined points for those places (ignore remainders), and a player must have at least one maki to score (Rulebook, p.7).

Puddings are scored only at the end of the game (after all rounds); the most puddings scores +6 and the fewest −6 (ties split), and they are not discarded between rounds — note the 2-player exception for negative scoring (Rulebook, p.9; end-of-game pudding scoring, p.10).

Yes — when only one card remains in each hand players simultaneously place that final card into their play area, then score the round; after scoring all non-pudding cards are discarded to prepare for the next round (Rulebook, p.6; discard/pudding exception, p.9).