I wasn't actively looking to spot differences, but the biggest differences that stood out to me were:
* Legal blurb and logos printed on toy.
* The two 'bumps' on the lower ramp on the G1 toy are absent on the reissue.
P.S.: I don't own a Gigastorm, so I don't know how many of these differences were present on that toy. Could someone who owns Gigastorm please confirm?