One suggestion would be to allow the player to catch some more criminals. As of right now it only allows me to capture 5 criminals until the game stops. Also, I would like the game to be a bit more challenging! Add something like a villain that can go after the cop.

Nice! I really like how Emilia, Ram, and Rem are moving around like they're sliding on their backs. It's pretty funny. One thing I would suggest is making it possible for Subaru to move from one side of the screen to the other, just like in Pacman. For example, if Subaru is at the edge of the left screen, and if the user continues to press 'a', move him to the far right side, while maintaining the same y-coordinate.