0.2.5

In this version:
-5 balls
-5 enemy balls
-simple movement
-high score

New Features :
-killing mode
-safe mode

Controls:
-numpad 0 ~ numpad 4 : Select ball
-WASD : add speed to direction
-Q : switch between killing mode and safe mode.

Notes:
-Each ball has one second kill mode

Known bugs:
-no bugs yet

Fixed bugs:
-no bugs yet