Guys, I think windgunner might be really good(please ignore the fact that I still managed to get hit somehow).
I don't use sprun/windgunner very often, but I decided to go with it this time.
I exploited the RR bug to keep the windgunner active after I got it on the 3rd floor
Damn shame I couldn't find more bullet passives, but platinum bullets and blank bullets work very well together.