The Kishin stabs Death the Kid with his finger, and ruins his chance to use a very powerful attack. But wait, he's up but unconscious and uses a massively powerful attack beating the Kishin's huge form!! Gah, now he's back up again in his regular form.
As for Maka, her figuring out that the Soul she was seeing was actually that little demon. That part was kinda lame when she saved Soul, and then Soul eat's the little demon.
Episode 51, wow, at the beginning everyone is beaten to a pulp. And the Kishin didn't get hit by the Genie Hunter, and the Kishin Hunter didn't work on him. He broke it. Also Maka was a Meister born of Weapon blood? That explains the scythes she used then after Soul went down, and she got hit by the Kishin's attack to protect him.
The last couple minutes are kinda horrible. The Kishin starts to lose his mind, and then Maka beats him with one stupid punch, and then bam, everything is back to normal.
Reminds me of how the Naruto movie final fights aren't all that great due to how those last fights end usually.