upbeat iris
Whe you are in a fight and switch to your gun and use right mouse button, you going in block mode(like you use your alt key). You have to wait for a long period of time and when you finally can use your gun your advantage is going and have to switch back to your main weapon.
opaque python
I have never had this problem, maybe go into the game settings and play around with the sensitivity.
upbeat iris
I'm not the only one and friend of my having the same issue also tweaked with sensitivity and didn't work