Mario bros goes up to 8 levels but level 7 and 4 are locked I don't think anyone knows how to unlock them.
To get to 2a you need to have a small mushroom and on level 2-3 go up where all the coins are and jump up the side
look up super Mario bros Cannon world 1 and level 1
you go up on top and keep running until you get warp pipe and go to the flag on level 3
As long as you keep leveling up your attack and hp will keep going up. You level up by defeating bad guys.
after u get bobbery go to the level up guy, talk 2 him, go to hooktails castle go to the room where u get the black chest key and blow up the wall bring it back 2 the level up dude and ur done
You go and through the level and meet up with Count Bleck, The fight the Mega-Robot-Luigi Boss.
Be Mario and go to the main lobby. Stand in the middle of the spot light and press x twice to be in perspective mode. Look up at the point where the light comes from and you will be taken to a secret level.
Go to the underground tunnel and hit that cucumber block in the water place, slide into water, keep going left until you see a switch, get on it and a door will open up, go into the door, get the star.
First, you have to be Mario. Then go to the castle and zoom in. Look up and point his head towards the source of light in the ceiling. Then you will go to a secret level. You will have to fly around in order to get to the platform and ground pound on the red ? switch. Hope this helps!
When you finish all the work on your level you can go up a level
up your butt