why didnt koola use his maxium power in movie

[Ravendust]

Yeah it was 'just a punch', but you've got to understand why it was effective (aside from being a Toei Punch).

1) (SSJ) Goku was being fed energy from Gohan, Trunks and Vegeta, his powerlevel/ki was constantly soaring.

2) Broly had been in his Legendary Super Saiyan form for some time, his ki/energy was constantly rising but his body wasn't transforming to compensate it. As a result his body was getting more and more unstable, like when you keep pumping air into a balloon. Goku acted as the pin.

 

[uncover bunker]

The way I see it is that Frieza's '100% Fourth Form' is akin to the Saiyan's 'USSJ'. It's a boosted version of a form for people who can't attain the next true transformation (Fifth Form/SSJ2 in this example).

That was my take on it anyway. Cooler's returned-Supernova death was unfortunate and unexpected on his behalf, he probably thought he'd win with that so saw no need to power-up further. Of course, by the time Goku fired his attack back at him it was too late anyway.

u were right...koola was underestimate goku's power..... he thought he doesnt need to use full stranght to deal goku until he fired into the sun....(that why he said he just as domb as his brother....he was regret that he should kill goku while he has the chance.... like brolly..too confident)

Yeah it was 'just a punch', but you've got to understand why it was effective (aside from being a Toei Punch).

1) (SSJ) Goku was being fed energy from Gohan, Trunks and Vegeta, his powerlevel/ki was constantly soaring.

2) Broly had been in his Legendary Super Saiyan form for some time, his ki/energy was constantly rising but his body wasn't transforming to compensate it. As a result his body was getting more and more unstable, like when you keep pumping air into a balloon. Goku acted as the pin.

he was too arrecant........he should kill them all while he had the chance but he just let it pass...

koola: 5,000,000(first form)
koola: 13,000,000(final form, i doubt he must be in 33% of he maxium....just like frieza)
koola: 43,000,000(his true power i guess...)
goku: 6,000,000(maxium)
goku: 15,000,000(ssj)

 

[tinymysticssj]

in all aspects of dbz everyone should know goku is meant to push beyond the limits. such as android 13 sucking in a spirit bomb to defeat him. back to the point when ur fighting for something u care about lets call this power a mothers love for her child. ur power increases as does goku for the world he cares about and his family he knows if he loses itll be the end so he puts up a 210% of energy to take him down. goku always pushes himself dont know who said it but when u see a powerlevel its the base of there transformation not there current lvl. sorry but cooler was a chump next to brolli.