Icons are able to have certain icon_states labeled as movement states. These special animations play when an atom is moving around the map. Since movements can happen at any time the movement animation doesn't always start on the first frame, it remains looping in the background and pops in at whatever frame according to the global frame counter.
This has worked just fine for most BYOND games over the years. Player sprites usually have a 4-frame walking animation, two frames of the character standing straight with the other two frames having either leg extended. It doesn't really matter what frame these animations start on because they look the same either way.
This isn't the case with more complicated animations. Walking cycles with a full stride or long animation sequences look very awkward when starting mid-step. What I'd like is a way to force movement animations to always start on the first frame of their animation sequence.
I realize this may break older games which is why I'm submitting this as a feature request rather than a bug report. This would probably be easiest to implement as a global setting, but it doesn't really matter to me how it's accomplished. As long as it's in I'll be happy.