Here is my variant on "Sumof2," tentatively called "TwoOrMore" (my previous posts edited together for brevity):
2 or more players (preferably 2 for now).
6x6 grid filled randomly with tokens with values from -18 to +18 (no zero), face down so that no one can see which token is which value.
There are 11 different-colored tokens with prime numbers that can be either positive or negative from 1 to 29 (1, 2, 3, 5, 7, 11, 13, 17, 19, 23, 29), also face down but off the board or in a bag.
A player reaches into the bag or otherwise picks a random prime-number token (Ex. 11). Both players must now find a combination on the board that sums to +/- 11. Because this is the first prime # token for each player, it must be a sum of two numbers (Ex. +18-7 = +11 or -13+2 = -11).
Each player, during their individual turns, flips over two tiles to find two tiles that would total the prime number token.
The first player who finds such a combination gets to keep the prime # token. Of the two numbers used to create the combination, the opponent gets to choose which of those two numbers stays on the board and where that number goes on the board while the player who made the combination keeps the other number.
With each successful combination that a player makes, the number of tiles needed to make a combination goes up by one. If a player has made three successful combinations and are now on their fourth prime number token, they'll need to make a five-tile combination (ex. +13+7-11-3+1 = +7). The opponent, though, does not need to follow this and follows their own schedule. So, for instance, one player may have "won" 3 prime-number tokens and, as a result, now needs to make a 5-tile combination to win the current token, which would be their 4th. The opponent has won only 1 token so they only need to make a 3-tile combination to win the current token, which would be their 2nd. Regardless of the # of tiles needed for a combination, only one will be put back onto the board each time by the opponent.
Also, all throughout the game, the number zero (0) is present. When a player takes tiles off of the board to keep after finding the combination to a prime number first, they have a chance to combine their tile total, in relation to how many prime numbers they've captured, to zero. If they can, they win automatically regardless of how many prime numbers the other player already has.
Ex. Player "A" has 5 prime number tokens already. As a result, that player has 15 tiles from the board (-18 to +18). If player "A" can match any 5 of their tiles together to equal 0, that player wins automatically. If player "B" only has 2 prime number tokens, that player would only need 2 tiles from the board to equal 0 to win automatically. A player may only figure out if they can "reach zero" with their tiles immediately after they win a prime number token. While they are figuring this out, the opponent may shift around the tiles on the board (not seeing the numbers, of course) until the player determines that they have reached zero or if they have not.
Anyway, I thought it'd be a nice wrinkle to introduce to the game so that the "opponent gets to decide what gets put back onto the board and what doesn't" has a little more strategic meaning as well as giving someone who is trailing a bit more hope of winning the game.
The winner is the first to reach six prime number tokens or the first to "reach zero."
Any thoughts about this are welcome.