protected void respondToInput() {
		if (isPressed[KeyEvent.VK_UP]) {
			if (s.getY() - SIDE_SCREEN_BUFFER > SIDE_SCREEN_BUFFER) {
				s.moveBy(0, -MOVEMENT_SPEED);
			}
		}

		if (isPressed[KeyEvent.VK_DOWN]) {
			if (s.getY() + s.getHeight() < HEIGHT) {
				s.moveBy(0, MOVEMENT_SPEED);
			}
		}

		if (isPressed[KeyEvent.VK_LEFT]) {
			if (s.getX() >= SIDE_SCREEN_BUFFER) {
				s.moveBy(-MOVEMENT_SPEED, 0);
			}
			
		}

		if (isPressed[KeyEvent.VK_RIGHT]) {
			if (s.getX() + s.getWidth() <= WIDTH - SIDE_SCREEN_BUFFER) {
				s.moveBy(MOVEMENT_SPEED, 0);
			}
		}
		
		// Projectile should only be shot on release
		// User gets one projectile per press
		if (isReleased[KeyEvent.VK_SPACE]) {
			s.fire( );
			isReleased[KeyEvent.VK_SPACE] = false; 
		}
	}