you can compress your media and sprites by using these two very important and free apps
"MediaHuman Audio Converter" this is a free application that will help you to decrees you sounds sizes specially if you have a lot of sounds in your game(HIGHLY RECOMMENDED)
and you can watch this amazing tutorial to understand how
"Caesium" is a free application that will help you to decrees your sprites sizes
although if your sprites are png format it won't help that much
but if you don't mind having black background instead of transparent it's going to be a good choice.