@Dream: Come on dude, you know the movies don't take place during the actual canon timeline. Cooler's Revenge is a perfect example of that. Goku was on Yardrat learning instant transmission, while in the movie that never happened.
@Jinbeifan1: that is because they focused a lot more power and remember the first time Goku did it be himself. then when he tried to blast him with the Kamehameha cool was unharmed and then Goku tried punching him again and it didn't work.
the only reason why goku and vegeta were able to do it was because it was to super saiyans instead of one and if they hadn't given him enough time to reform he would have be immune to their next attack.