Improvements
You need to make less sound effects sowhen your playing the game you won't here a big crash of "BOOM" "POW". You need to animate the planes better so that there not sliding randomley all over the screen.
The bombs need a lower blast raduis because when those bombs go off the cover about the entire screen!
Less random items hovering all over the screen so you can atleast move around without collecting those jewels.
Smaller enemys so you can move around a little bit more.