The game is now at: http://dapur-uang.com/games/catching-a-star-for-wulan/
Reading the links fisholith gave me I made some changes with the coding, especially the collisions. Which is basically almost like ikke2902 describes.
I use groups and subgroups which I deactivate when not in used, for example for the bosses.
I make sure things that only be executed 1 time, only 1 time executed.
I give up some animations that requires spawning many objects.
It is a bit better now, but ... it is still super slow when I test it on my samsung youth handphone.