Like any good word game, the concept of Word Fu is simple. You'll be given seven lettered dice and a set time limit. The object of Word Fu is to spell as many words as you can with the seven letters you've been provided. The challenge here lies not in the gameplay, but in your own familiarity with the english language.

The gameplay is simple, but that doesn't mean it's without nuance. At the beginning of each game you'll have the opportunity to try and develop the best letter set you can in 20 seconds. Since each die is six-sided, changing the letters offered with be done by rolling the dice. You'll change your letter set by flicking the dice individually or shaking your iPhone like a Yahtzee cup and giving the whole collection a shuffle.

Once in the game you'll need to build as many words as you can. Each letter has a different point value, and the longer the word you build the higher the score multiplier grows. As you progress through a round you'll earn different power-ups that will help you to build better words, thereby building a better score. One modifier, for example, will let you flip a die to another letter. Another will freeze time so that you can build more words. Given the tight time constraints of each round, every second helps.

By default, the game plays out in 45 second intervals. You can tweak this to play the game under a number of time constraints ranging from 30 seconds to 2 minutes. You can also change the ruleset to “Shaolin style” if you're looking to up the challenge. Unlike the regular game, which will allow you to use the same letter die multiple times in a word, Shaolin style only lets you use it once. If you're playing with only one “s” in Shaolin style, don't expect to be spelling “business” any time soon.

One of the things that really stands out about Word Fu is how verbose the dictionary is. All too often with word building games players will find themselves constructing perfectly reasonable words that the in-game dictionary doesn't recognize. During our six or so hours of playtime we didn't encounter this problem once. In all of my years enjoying word games, this has to be a first. For a game to have such an extensive vocabulary is downright unheard of, and beyond commendable.

Another place Word Fu sets itself apart from the crowd is in its attempts to turn a traditionally single player experience into a competitive one. After completing a round you can instantly send a message to your Twitter or Facebook challenging others to do better with the same letter set you used. It's a great idea, but it misses the mark for a few reasons.

For one thing, Word Fu is only playable on the iPhone and iPod touch. This means that all of your Facebook and Twitter friends who want to take on your challenge without the device will simply be directed to a piece of advertising for the game. Had ngmoco offered up a web-based alternative for those looking to tackle challenges it would have definitely helped to grow that competitive experience they're looking to develop (not to mention introducing a legion of potential customers to the pleasure that is Word Fu).

Like most word games, Word Fu is limited by your own vocabulary. If your lexicon is light, your interest in this game will be too. But if you're an avid Scrabble fan looking for that next challenge, Word Fu offers up a fresh take on a common wordplay mechanic that veterans of games like TextTwist will delight in. Publisher ngmoco has had a flawless track record on the iPhone so far, and Word Fu does nothing to diminish that.