Star Coins
One of the differences in this version of the game is the addition of large stars located in each level. Each level houses three of these large stars. As you collect them, the meter with three stars at the top of your screen fills up. However, nothing seems to happen, even if you collect them all. As you collect them, though, something is happening behind the scenes. If you collect all three coins in every level, you will unlock Star World, which is level 9. The level 1 coins unlock level 9-1, level 2 coins unlock level 9-2, and so on.
Stars in Star World
Each of the levels in Star World also contains three large stars. Just like in the other worlds, finding all three stars in each level doesn't appear to do anything as you progress through the level. However, obtaining all of the stars -- a total of 24 -- will earn you an award at the end of the game. After you complete the game, you will earn a large star that is added to your profile.
Save Anywhere
Unlike the original Mario Bros. game, "Super Mario Bros." for the Wii allows you to save your progress as you go through the game. However, you can only save at specific points during the game. If you don't make it to a save point before you die or need to stop playing, you lose some of your progress. However, once you complete the entire game, including Star World, you obtain the capability of saving the game at any time.
Game Ending
When you beat the game, the ending scene plays, showing Princess Peach asking you if you have ever seen the secret world. This means you have earned access to Star World, or world 9. Once you play the game again, including Star World, you will see an alternate ending. During this ending, Princess Peach asks you to tell her about her adventures again. This is the ending you will see each time you complete the game after earning level 9.