Atoll is a tight open-drafting, tableau-building, engine-building optimisation game designed by Jan Štěpánek and published by Albi. It features beautiful marine life art from Martina Lásková and Michal Peichl.
Over four rounds, the 1-4 players are drafting cards from a market display to add to their individual tableaus, each of which represents an atoll with its coral reef. Coral cards are added checkerboard style: always diagonally adjacent to the corals already in your atoll; while cards representing fish are always placed orthogonally adjacent to one or more of your coral cards. Each creature card will indicate how many corals it needs to be adjacent to: if a fish requires two adjacent corals, you won't be able to place it unless you can position it so that it has at least that number of coral symbols on the coral cards adjacent to it on at least two sides.
Notwithstanding the tropical theme, Atoll is actually a eurogame, and it's one with an economy that's very tight, especially in the first round. There are other resources (plankton and fish scales) but it's money you'll need to buy cards. Each round you must choose whether you want to limit access to scientists or whether you're opening up your atoll to tourists. Tourists bring in more money than the scientists but they also cause pollution, which will be an impediment to your reefs' functionality by blocking the actions on the coral cards. If you don't purify the water and remove pollution, it will also impact on your end-game scoring...
If you manage to build a productive 'engine' - ideally with creatures that have a symbiotic relationship - you'll be better resourced in the later rounds. The idea behind Atoll is that players are pushed to create balanced ecosystems that properly support their marine life. You ultimately score points for advancing your fish population by ensuring they are adequately fed. Tho' some marine creatures consume plankton, others prey on smaller fish, so will reduce their population, at least within your own atoll: an unusual feature of the game, in contrast to similarly themed games like Oceans (North Star), is that when a creature 'hunts' and feeds on fish in an opponent's atoll, your opponent's fish population is not reduced. Tho' Atoll is competitive it is most assuredly not a 'take that' game.
This is a game that already has great replayability but, nevertheless, Atoll incorporates 'advanced rule' expansions that further add to the challenges. These include scoring for biodiversity and the addition each round of event cards that give a rules-tweaking hindrance or benefit to all players. However you choose to play, Atoll is a challenging and rewarding puzzle optimisation game.