It's Hexcells but it's free and... not good. I am not sure if it gets less mind numbing and tedious later but I honestly gave up after a dozen levels. It's more busywork than puzzle, and definitely lacks the beauty and aha moments that Hexcell has. Heck, even the procedurally generated Hexcell Infinite puzzles are better than this. I am giving it a 1.5 because it's free.