This is the demo of Dragon Quest IX: Sentinels of the Starry Skies for the DS. This is actually a video loop and not an interactive demo where you can play the game. These are very common, so always one is available to add to your collection. There are many variations to this including distributions available.
There are two back sticker variants to this game. The one as shown to the side is the more common one with the store # text and also has a small barcode. There is also another one shown below without the store # text and has a much larger barcode.