I'm still waiting for the smartphone game that makes it onto my list of best games of all time. I'd read a lot of good things about the game 10000000 (i.e. 10 Million), a game with an unwieldy title that got good press, particularly from Game Informer, who apparently named it their "Best Mobile Exclusive" title of 2012
I picked up the Android version, and it didn't take me long to realize that the game's setup is essentially the same as the game Puzzle Quest, which was a puzzle-RPG hybrid that appeared on the DS. I had played that game about six years ago and thought it wasn't bad overall, and had actually played it all the way through to the end. 10000000 has a unique take on the tired match three mechanics, where instead of moving pieces around or swapping adjacent pieces, you can slide a row or a column (which wrap around the screen). The goal of the game is to earn 10,000,000 points in one round, and this is achieved by working your way up through the levels, which feature more difficult enemies, but also a higher multiplier.
Basically I found 10000000 to be reasonably enjoyable until I realized that despite the more welcoming retro art trappings, the game requires even less strategy than Puzzle Quest. Puzzle Quest requires you to be very deliberate about your movements since in the main modes you alternate moves with the AI, but in this game just making matches of three of the type you need as quickly as possible usually accomplishes enough for you to progress, i.e. you don't really have to think about chains at all. There are missions you have to complete in order to progress to the next ranking and items you have to strategize about using, but otherwise the game is pretty mindless and the enemies don't really require any special strategies.
In short, this definitely wasn't a complete waste of time, but 10000000 wasn't a game that I felt compelled to continue, either. The match 3 genre continues to grow, and I've already put some time into the next one on my list. That one has already been a bit more of a time suck, though, but we'll have to see how it holds up over time...