Replay speed control with pause
When I replay a session to understand what happened, I want to slow down at the interesting part and skip the forty minutes of nothing.
Variable speed plus pause plus step-forward-one-tick. The step function is the one I'd use most, at the moment of an entry I want to advance one tick at a time and watch the conditions change.
Right now I watch the whole thing at one speed and miss the moment I was trying to see!