Thank you for your reply. I guess I've figured out what happened. The problem is the game's resolution. As I can see, you have used the 1008 x 624 resolution. I'm using 1104 x 624. So, I've tried your reoslution on my game and voilá, the FPS has increased. But why just a few pixels more have this great impact on Visustella Battle Core Plugin, beats me.
Oh, and I've loved your game! Hope to see more projects from you soon.