useLoadFont loads a bitmap font (an image plus a file saying where each character is) and createText writes with it. style.fontSize is the height of a line in pixels: the arcade font is 8 px tall, so 32 draws it four times as big and stays crisp.
The score is plain data, so score.text = ... shows on the next frame. The last line is written in lowercase, and this font has lowercase letters, so it is drawn as written; a font without them would draw its capitals instead.