The costume name is in the top left. To change the costumes, you use the left and right arrows. To see a list of all nine of the costumes, you press the up arrow, and to hide the list again, you press the down arrow, which will appear where the up arrow was. You can change the size by changing the slider. You can't make it any smaller than size 25, and no bigger than size 100.
I got all of the sprites from http://emojione.com/, where you can find tons of Emoji. I got the music from 'Time Is An Illusion' by @-TotallyEpic-. All of the programs were made by me.