Hexcells official intro
I recently tried this PC game, then have been amazingly addicted to it. It is not depend on your speed, the game is much more like the custom mode of minesweeper without guessing. If you have tried another online game named fill-a-pix, then welcome to another similar game The target of Hexcells is to solve all levels, a group of new levels will be unlocked if you have perfectly solved former easier ones.
You can map hexcells to minesweeper like:
The yellow cell=unknown cell
The blue cell=mine
The black cell=number
Everytime a new unit is introduced to player, there will be a trival level teaching you how the unit works. In the mean time new skill is also needed. 1 or 2 mistakes is allowed for some very hard levels. Sometimes you have to count the rest of mines.
Only your left button and right button are used, and the original setting is in reverse to minesweeper. For better mapping, you can change your setting when you are installing the game from steam.
If 30 levels don't satisfy your need, there are:
Each series is harder than former one.
I think 6-2 level of Hexcells and 6-4 level of Hexcells plus is the hardest of each series. 1.2 hours for me solving the Hexcells, 5 hours solving the Hexcells plus
Only 1 hamburger is needed to pay for all the three. If you have interest, I strongly recommend you to buy all of them, you can't stop playing!