Hexcells and its standalone expansion, Hexcells Plus, are now available on Steam for PC, Mac and Linux users.
Both games play a bit like the Picross series - players are presented with designs made out of hexagons at the start of each level. The black, numbered hexagons tell a player how many pieces of the final design are touching the black spaces, but players need to determine which of the orange hexagons are extra black hexagons and which are hidden blue hexagons. As players mark each orange space, the correct choices will turn blue, while miscalculations add to the Mistakes counter of a level.
Each game is $2.99, but they can also be bought in a bundle for $4.99. Hexcells seems like the sort of puzzler we would laugh off the complexity of, right before frying our brains over levels like this.