I'm also having trouble with this. Thought It was simple but Doesn't seem to be working for me. Thought I'd try and get a walk anim going before I got it to move.
Got sprite anim 'Run' with frames 0 - 9 at speed of 12 on loop with 0 repeat count. Event sheet says 'keyboard - right arrow is down - set anim to "run" (play from beginning) this wouldn't work so added Start animation from beginning also have keyboard on right arrow released - stop animation.
Cancel that, it's started working! horay :) Seems to be inconsistancies with these games working on my browsers. they work then they don't. or they work on preview but not after exporting.
So why do you set the animation speed on the system rather than in the animation options? I have anims at different frame rates and doing it this way you have shown me plays them all at different speeds.