i was going to post myself that gravity punch does nothing. it has an effect, but so weak, that i dont see how it's supposed to be useful. if you knock out enemy and try to punch near body, you will see it pushes body towards you, but very little. i was going to test it more, but i'm not sure i will find how to use it. it would actually be useful if it was much stronger and would help your punch hit target more precise, so even if you miss, it still gravitates to center of the body. but i'm not sure how much this is possible, as it may already be too late to change your attack trajectory.
as for banana and other perks, they sometimes dont activate. me and my friends saw various perks that simply didnt work. this will be fixed