Lars Jansen's Perfect Numbers looks on the face of it like an easy-going set collection card game but, in our plays at Board's Eye View, we've found it to be a remarkably cutthroat 'take that' game.
In Perfect Numbers, the 2-4 players are creating four stacks of coloured cards; just three if you decide to play the more 'interactive' (ie: even more cutthroat) variant. There's a market of four rows of cards: one row of 3, two of 2, and one row of 1 card. On your turn, you take all the cards in one row and add them, if you can, to the stacks in front of you. If the number on a card is higher than the number of cards in that stack (including the card you are playing), you just add it. If it exactly matches the number of cards in the stack, it's considered to be a Perfect Number: you complete the stack and move it to your scoring pile where every card will count as one point in end-game scoring. If the card value is lower than the number of cards in the stack then you have to discard from the stack the number of cards equal to the value of the card you played.
That's the set collection element. However, you'll soon find you are picking rows of cards from the market that you are unable to place in your tableau because they are in a colour that's not in any of the four stacks you have active. You're not allowed to start a fifth stack but what you can do is play cards to an opponent's tableau. These follow the same rules except that if your play creates a Perfect Number (card number exactly matches the number of cards of that colour in your opponent's stack), then it is you rather than them that collects and scores the cards. Likewise, if you play a card to an opponent's stack with a value that's lower than the number of cards in the row, their discards go to your score pile.
You can see how canny players will spot early on that it will often score you more to pick cards for a 'take that' play on an opponent's tableau rather than those that extend your own. There are bonuses to be had from topping off your stacks with a 5, 6 or 7: playing a value 7 card as the seventh is a stack will net you a five-point bonus in addition to the seven cards that'll go to your score pile. Of course, building up a row of that size could be a push-your-luck gamble because it will make you a juicy target for lower-value cards...
Just to keep players on their toes, there are three types of special 'action cards' that can turn up in the market display. The 'steal' card lets you take the top card from an opponent's stack and either discard it or add it to one of your own stacks. The 'protection card' lets you place it, or a card already in one of your stacks, as a face-down card in any stack. It'll count as a card in any stack that it's in and while it is the top card in the stack, opponents cannot add to that stack or steal from it. Finally, the 'move' card lets you move the bottom card to the top in one your stacks. This will only be of use if the moved bottom card is the Perfect Number, so lets you score the stack. You can allocate one of your stacks to store action cards but you cannot retain more than one of each type; you can, however, chain them so that, for example, if you have a 'move' card saved from a previous turn and you pick up a second 'move' card, you can use them both on the same turn - including, for example, to manipulate a stack so that the second card from the bottom becomes the top card and so scores as the Perfect Number.
Publishers Jolly Dutch have highlighted that Perfect Numbers is an eco-friendly game, and that's reflected too in Hoang Pham's artwork. If you're looking for a highly interactive fast playing 'take that' card game, Perfect Numbers could be the perfect choice.