Fixes for bad things you people encounter:
Half Sinking in to floor: make sure your character's registration point is at bottom. to do so, double click the chars mc, make sure that the x is at the perfect bottom. if it is not, it must be. to do so, copy the character from the mc, delete the mc from the library, create a square, right click, click conver to symbol, select movie clip, name the char and WAIT! make sure the squares (9 squares) black square must be at bottom. if it is not, click the very bottom square. then click OK!
Character falling through ground: make sure the whole ground is one movie clip, if it already is, make sure you have the instance name called "ground". to do so, click the movie clip once for the ground, window > properties (i dont know), and at the very near part of where there is a dropbox saying "movie clip", it says "", enter the instance name "ground', Your'alllllllllll set!!
 "Epic Platformer Tutorial"){kind=icon}