I have some problem with 2D physics.
Only one object, one platform - but already player physics work wrong - it fall to sky (up!), if i add to it more mass - it fall down very slow, without any acceleration. Anyone can help me? Test project there:
https://github.com/Newbilius/unity_dave2
Sorry If i select wrong section or forum.
Just recreate all objects… and it work. I just don’t understand… Unity so buggy? 
Everything is buggy when you’re doing it wrong. Go to asset store and download the free example project. Then read the documentation. It’s Box2D, so you’ll need to learn how that works. Most likely you had some really bad settings before, or layers. Without you spending time learning it, it will happen again.
I find problem - i use “apply root motion” on animator. My fault. I’m sorry for the time taken away from you.
But now i know, how friendly unity3d comunity…