Hello! Hello! I feel like we should review New! super mario bros.(DS) first. Off the bat you have that feeling that this game is going to be a great game, staring everyone's favorite plummer, mario! In the first level you get to use a mega (as in MEGA) mushroom. the fun lasts to world five, when the ice starts to "melt". That reminds me, there is an cannon in world 1 and 2 that gets you to world 5. The cannon in world one is found by getting the shell suit. In world one tower get up to the point where you find the green pipe that shoots you past the door. As you come down wall jump onto the platform. When you are in the room and have collected the star coin, look around the room. See that space up in the corner that never gets blocked? Jump in there. Once that is done, spin dash. Whatever you do, do not jump into the yellow pipe. Once you are done,(you need to spin jump) enter into the pipe you've unlocked then pull down the flag outside. The second cannon is a lot easier, and I think that you can unlock it all by yourself.
There is another mode that you can play after you beat the main game: Challenge mode. After beating the game you just have to hit Start in the world map and enter the following code:
The challenge mode puts a forced scroll on all of the levels, so you can't back-track.This is a video telling you how to get world one cannon: