WarioWare Touched! is a fun game to play but considering it's short length, isn't worth a purchase.
If you've ever played a WarioWare game before then you know how the rhythm of the game works. Generally, you will have three to five seconds to complete a certain task on screen. It will display an ambiguous one word clue of what you have to do with the current minigame and then you have to, well do it.
An example of a particular minigame is the screen will show the word "Slice!" and some assorted fruit will fly by the screen. Using your stylus, you have to slice the on screen fruit within the time limit.
The minigames are fun and unique and the game contains some humour and some nice unlockable content but the one big downfall of the game is that it's too short. WarioWare Touched! can probably be completed in about 2 hours of continous playing. Most people I know beat the game the day they purchased it. The fact that the game isn't really difficult probably doesn't help its length either.
Upon completion of certain sets of games, you can unlock certain small applications which are stored in the 'Toy Room' part of the menu. They're fun to collect but most of them won't hold your attention for long. There are a few gems you can unlock but they're still not too interesting or fun to play.
To summarise, WarioWare Touched! is a fun and addictive game to play that makes great use of the DS's capabilities but isn't a recommendable purchase due to it's ridiculously short length. If you know someone who has a copy, ask to borrow it from them instead of buying it.