How it was to be responsible for the technical part of animations on Borderlands 2?

Hello, Gearbox Software!

I started to play Borderlands 2 three weeks ago and was pretty impressed by how good the game looks right now consider it is 7 years old.
I really like the story in this game, awesome jokes and small talks that you hear while playing the game.
Also, I think that enemies are really interesting to play against and they seem really smart, especially Rat guy who can pick dropped loot or steal something from you, also, I like how enemies become stronger when your level is growing, they start to move faster, type of their movement is changing too, that’s kinda unique in our days. I guess it’s a good AI system.
I really like the Art style of the game but guess it’s an obvious one, but I must say that I was really surprised by the animation quality in the game, how nice it looks, how awesome enemies jump or climb on the edge where you’re standing with nice animation.

I’m a technical animator by myself, so kinda really like when animations are done well in the game and I was thinking that maybe you will tell us “How it was to be working with technical part of the animations?” “What the biggest challenges that you met?” “What results in animation are you most proud of?” “What had you to sacrifice but really wanted to implement?” “What thing was the easiest to do, but still looks really nice?”