well, for the wall blast, you know the cannon where you shot yourself to the star? shoot at the corners of the walls where the rotating plank thing is. then the star will appear. as for getting luigi, go to big boo's mansion and beat the 2nd mission and the next course you should go to the same place where you got the star for the 2nd course and follow the voices (laughs really,) and jump into his painting.
thanks to ieatwyverns for the awesome sig. btw, the letters above vengence is bliss, my screen name
dragon quest monsters joker is the best game possible besides ZELDA
WOOT ZELDA AND DRAGON WARRIOR!!!!!!