Really nice work for your first game jam. Obviously sound/music would have been nice, but you did really well with the theme. One recommendation I would have is control-wise, I *think* it might have been easier to have WASD control the left player / arrows control the right player (regardless of which color is on left/right). What happens is that you forget which player is which and you're constantly using the wrong keys. The visual on the screen isnt' matching the keyboard layout once they flip around and it gets confusing. Having WASD always control whichever character is on left and vice versa would have been a lot easier.
Nice job!