How Battle of Gods should be

About the same up to the point that Fat Buu gets Bills' pudding.After that...

Bills one shots Buu.
Everyone turns to Gohan,expecting him to save the day.Then,everybody falls upside down when they see Gohan
totally drunk,unable to realize what's going on,let alone fight.
To everyone's surprise,Vegeta transforms into SSJ3.Then,he makes a speech,with flashbacks,babbling about what he
went through to achieve the form.Roshi says something like ''such power,he might have surpassed even Goku''.
SSJ3 Vegeta attacks Bills with a flurry of punches and kicks,the god dodging every single hit,but,when the Saiyan
manages to lay one successful hit,Bills gets annoyed and knocks out Vegeta with one hit,like he did to Goku.
Nevertheless,the full blooded Saiyan has bought enough time for Goten and Trunks to fuse.
Gotenks goes SSJ3 right away.A semi comical fight commences,with Gotenks using all of his signature attacks,
resulting in plenty of gag scenes.The fight ends with Bills spanking Gotenks,knocking him out of his SSJ3.Soon after
that,the kids defuse.
Videl brainlessly tries to fight Bills,who slaps her.When Gohan sees that,he gets angry and snaps out of his drunken
state.He powers up to his mystic form and attacks Bills,delivering several hits.After a fair fight,the god wins.
Goku returns,they summon Shenron and ask him about the secret behind SSJ God.The dragon replies he doesn't
know and disappears.This makes Bills angrier than ever and he decides to destroy the planet without further ado.
Goku thinks of fusing with Vegeta,but,then,realizes Vegeta's out cold.
In a desperate attempt,Goku blinds Bills with solar flare.Then he starts forming the spirit bomb.He finishes the
sphere the same moment the god regains his eyesight.He launches the sphere.Bills says ''hmf,what is that puny
ball supposed to do?''.He powers up,a purple aura surrounding him,and kicks the ball back to Goku.The exhausted
Saiyan has no stamina left to repel it and is just watching it in horror coming towards him.
Then,something totally unexpected happens.Because Goku has a pure heart,instead of destroying him,the spirit
bomb is absorbed into him! This turns him into the legendary SSJ God.
Bills is now content that he has at last found a power to rival his.He powers up to his 100% and the two of them
start fighting in outer space.After a titanic fight,Bills wins by a hair.He carries Goku's body back to Earth.To
everyone's surprise,he says he won't destroy Earth,because he wants to fight Goku again someday.He smiles to the
pure hearted Saiyan and tells him to train hard,for one day he'll return.

Other differences...
-Goku permanently gains the ability to go SSJ God.The movie ends with an annoyed Vegeta saying that,one day,
he'll unlock the form too and surpass Kakarrot,at which everybody laughs.
-Whiss remains just a sarcastic servant,whom Bills just allows to talk to him like that because they're practically
family.I never liked the idea of him being another TFS Mr Popo.