If you have played any of the other New Super Mario Brothers games, then this is pretty familiar territory for you, not much has changed really from any previous iterations you might have played previously.
You go through the few paltry worlds given to you, collect coins and star coins, beat a world, rise wash and repeat. While the gameplay is about as fun as a side scrolling platformer can be, the game is altogether too short. It didn't take me long to burn through all of the worlds and I found myself done with the game.
If you are the completionist type you can replay every level trying to get all of the star coins, and you can play the Coin Rush mode, but I find both of these options a little lacking in terms of actual game content. If you absolutely gotta catch em' all then I suppose this will extend your enjoyment of the game a little bit, but I find it to be boring and not worth the time or effort to go through all of it.