This game is clever, very clever. As the other reviews will tell you it's a mix of Minesweeper and Picross played on a Hex grid instead of a square one. And that's just the start of it, with additional rules introduced slowly that will definitely keep you challenged.
This is the first Hexcells game I've played, even tough it's the second one in the series, because of this the puzzles might have grown harder a bit faster than you might be used to in a game (I know I had to get used to it). I assume Hexcells introduced the basics at a more leisurely pace, however Plus also starts with these basics and assumes no prior knowledge of how to solve these puzzles.
All in all there are 36 puzzles, which range from "engaging" to "fiendishly hard". Later levels are unlocked by playing earlier levels and doing well on them (rated on number of mistakes made, there is no
There are some points where I feel the game could have improved, primarily a mid-level save functionality and the ability to mark black cells as done (or have this done automatically), but these are small issues that do not detract from the entertainment.
A solid game that I recommend to anybody looking for a puzzle game that doesn't follow the same tired concepts.