Puzzle games thrive on simple design and intelligent challenge, and 4444 certainly accomplishes the former.
It's a game that's so simple it could also work as a physical card game (though why bother when you have a touchscreen?) and that alone makes it worthy of attention from anyone who likes a bit of quick-thinking action.
But, as you'll see, you also need a high tolerance for frustration, and that could rule out a lot of casual coffee time gamers.
4444 asks nothing more of you than to turn the whole screen a single colour. It begins by dividing it up into blocks, with a row of different coloured tiles waiting to be placed on the game board.
So let's say the screen is split into quarters, with three red squares and one yellow. The next tile to be placed on the board is a red one, so you tap the yellow square to turn it red, and the puzzle is complete.
Naturally this is pretty much the first level of the tutorial, as 4444 wouldn't be very challenging if that's all it asked of you.
As the game goes on, the screen is split up into more and more squares, and not all of the same size.
Should one of the quarters described above also be split into four, changing all those adjacent blocks into the same colour combines them into a larger square. You're now back to the whole screen being quartered, and easy to complete.
This is where the challenge is found. As with tetronimoes in Tetris, you have no say over which coloured tile comes next. You might need a green square to complete the puzzle, but you can see there are two blues and a red before you get to the required green, so figuring out exactly where to place each one is the crux of 4444's gameplay.
Further complicating the cause are blocks that change into whatever colour is next to them, and caged blocks that can't be changed - although they can be destroyed by lightning bolts, which also split larger blocks back into smaller pieces. You have to use whatever tile is dealt next, however, so if that means splitting up a completed square, so be it.
In principle, 4444 is a great idea. Its incredibly simple design aligns with the likes of Bejeweled, Tetris, and even retro classics like Simon. But for some reason it can be somewhat annoying.
For one thing, you score most of your points not by solving the puzzle, but according to how quickly you complete it. And 4444 is a harsh mistress, so anything less than firing each and every tile at the game the nanosecond it arrives generally lands you with a low score.
Given that you can only see the next four blocks in the line this seems rather unfair, and means the more challenging levels always require at least a couple of test runs. This is less than satisfying, as it feels more like a process of elimination rather than puzzle solving.
Similarly, if you make one mistake, you might as well restart the level, as there's no recovering from a test or an error. There's a finite number of tiles available, so get one wrong and it's time to quit.
We can't help but think that 4444 would work better if you were scored on how many moves you made, and not how quickly you worked through the only allowable options.
A couple of mini-games are thrown in to change things up a bit, including an on-going round and one where you're racing against blocks being split up before you complete the level, but these suffer from the same sense of frustration that plagues the main gameplay mode.
This isn't to say 4444 is a bad puzzle game. It's a clever design that builds a challenge from some very simple rules of play, and that's to be applauded. But if we wanted a colour-matching game, we might be more tempted to play through Kami again first.