Smash by sheer numbers. There really isn't anything Kratos, or anyone else, can do about Super Sonic. If we let Pit use the Great Sacred Treasure, he'd simply be way too fast for Kratos or Zeus. After the two gods are done, Samus' technology (including the invincible screw attack) wipes out everyone else. I'm not really sure Kratos could take out Samus either way.
That's before we get into Ganondorf who is basically unbeatable without certain methods that won't be available to the All Stars, Rosalina's ill defined cosmic powers, and so on, it's a pretty clear victory for Nintendo.
Anyone who's played Xenoblade...
*spoilers spoilers spoilers*
Knows that Shulk is basically a god by the end of the game and can literally recreate the damn universe with the Monado. So... there's that too.