Thank you for the feedback! To be honest, I tried to put some background effect(like horizontal line, explosion line), but the outcome seems like doesn't look good, so I just settle with plain pink. Do you have any suggestion what should I do? I am still new with pixel art, there is alot to learn 
I like you style, but I think you shouldn't leave the background just plain pink.
Oh well, of course! Of course not.
I think you will find out it someday and rework this pixel. I hope.