A couple of movement bugs I've found:
-While running, if you rock the strafe left and right keys back and forth (easy to do now that the WASD layout is commonly used), you can move noticably faster than the player's ordinary max speed.
-The wallrunning bug that dates back a long time in id-engine games is present where moving along walls at a 45 degree angle allows much faster than normal movement speed.
I don't think that we'll fix this.