Gridcannon is a tactical solitaire card game, based on the original design from Tom Francis - creator of hit indie games Gunpoint and Heat Signature.

Featuring three all new game modes to master, and six unique deck artworks as well as flexible difficulty options!

The goal of Gridcannon is to kill all the royals using the grid to set and trigger payloads.

The game begins by drawing cards and laying them out a 3×3 grid, skipping the center position. If any royals are drawn during this, they are put on a separate pile instead and cards are drawn until the grid is complete.

Any royals drawn while dealing (and any new royals drawn) will be placed on the outside of the grid, adjacent to the card nearest it's own value (color, and number). So, a Jack of hearts would go next to a 10 of hearts if it was on the grid.

Number cards are placed anywhere on the grid, as long as the card it is being placed on is not a higher face value. If a card is placed on the edge, and there is a royal on the opposite side of the grid, then the two cards between the royal and the card just played are added together. If the value of the two cards total more than the royal face value then the royal is "killed". Jacks are 11, queens 12 and kings 13.

If the player can't place a card on the grid, because all cards are of a higher value, the card may be discarded or placed on a royal as armour. Armour is added to the face value of the royal when calculating damage.

This isn't the complete ruleset, but it gives an overview of how the game plays.