The oddly titled puzzler is the first outing from developer TrueThought  and is similar to the recent game KenKen that's been running on the New York Times website.
Also, it's been DEVOURING MY SOUL.
Avoid it if you can, or check out the free demo if you have hours and hours free for the rest of your life. There are literally tens of thousands of puzzles in there, all math-based, and covering a broad swath of skill sets. At the end of the day, it's all simple logic. You have a square grid. Like Sudoku, you can only use each number once in a row or column. Numbers are grouped into "cages", and the numbers in each cage share some attribute: maybe they're all even, or they add up to 15, or some such. Based on the clues, you have to sort out what numbers go where.
They get progressively more complex and the grids get larger as you advance, but on any given level of difficulty (of which there are like 40), there are hundreds of puzzles (800 is typical, especially at the beginning), of which you really only have to beat one to advance.
Couple the uber-addictive-ness of it with the Steam Achievements (I'm kind of a sucker for achievements) and you get a puzzler well worth the $15 that is a complete time sink.
So, save yourself, 'sall I'm sayin'.