For everyone's inner scientist (or for those of us who have a soft spot for high school physics), Atoms Puzzle just might be the free-time iPhone indulgence. Optimized for iPhone 5 but available universally, and requiring iOS 4.3 or later, Atoms is a streamlined, brain-stretching way to pass an afternoon.
The game builds on basic scientific observation to draw out the objective, and it's even in the pop-up directions: Larger atoms convert smaller atoms within their vicinity to the larger's composition and structure. However, one need not have the barest acquaintance with atomic theory to play a successful level of this puzzle. Building on the conversion idea, players are to take a varying number of differently-sized atoms (which are red) and convert a stationary pattern of other atoms (colored green) to the first group's color. This sounds simple enough, but the player cannot merely place the red atoms in any lackadaisical formation. Depending on the size of the both color atoms, the green ones may only shrink in size, not being converted completely. But this shrinking can be used to one's advantage, as this makes it easier to convert the green atoms.
The beginning player is given thirty levels of increasing difficulty, though there are a total of 174. After the thirty have been mastered (which is very doable for the reasonably determined player, as I did it within probably less than an hour), the player has the option of paying an in-app fee of US0.99 to unlock a new "pack" of levels (the others can be unlocked for free after purchase), but retrying the first thirty is entertaining for the short of cash!
As players complete levels they are greeted with differing affirmative phrases ("Nice work!" "Outstanding!" "Fantastic!" and so on). This may seem like a small thing, but the fact that it was not some immobile stock phrase was refreshing and signified attentiveness on the part of the developer. The player also has the option of sharing the completed puzzle to Facebook. This communal aspect of the game also shows up in its option of many two-player levels. Users can also play levels by challenge, where they can create their own red atoms to try and solve the puzzle, while paired against the best score of other players. They can also go back and try to solve in fewer atoms as well.
A nice aesthetic feature of the entire game is that players are not restricted to only red and green atoms, but can mix and match several different colors as many times as they like. Over the course of playing mine, I switched colors several times (once or twice in the same level just for fun), but all of the colors work well together. Another thing must be said about the graphics, and that is their elegant simplicity. While the game is very streamlined and simple, it is far from ugly. Clearly, time and care went into creating a game arena that was pleasing to look at but which was free of unnecessary frills and distractions. One can concentrate on the gameplay while not being jarred by elementary graphics or loud colors.
The other helpful feature of the game is the redo function, where stuck players may undo all of their choices and go back to the level's beginning I found this trick invaluable, especially when I got hopelessly entangled on later levels (cough, sixteen, cough). Still, the puzzles are hardly infuriating or frustrating, and a player willing to expend the necessary thought and observation of detail will find solutions (likely one of several possible, including at least one which does not require use of all the atoms) relatively quickly.
Science was probably one of my worst subjects in school, second only to math. I remember basically nothing from any of the science courses I took in high school or college. But even though this game is based on a basic fact of physics (which, if I ever learned it, it has long since been forgotten), I had no trouble whatsoever connecting intellectually and emotionally with the app. I was invested in it, eager to find out how to solve each puzzle, and found it so entertaining I thought nothing of replaying the same levels over a second time. I really have no constrictive criticism of Atoms Puzzle, and would be delighted to find more games in the future from its developer.