you can do that, Use a blank keyframe at frames 11 and then 19, then 20. Then start the new animation on 20.
I’ve seen this foul up movies occationaly. Save your work often and as many different consecutively named files and you should be fine though.
The animation was pretty good. Not as good as some that I’ve seen, but you’re getting the feel for how they move. I’d give you a 75 off the bat. I’m not as tough as some critics though. 
You’ll get it though. I am not really all that sure about the thick lines on those figures. I think they should be thinner.
You’re next step is to develope a plot. Try writing a story out. It needs to be writen with zero dialogue, of course, which is a serious challenge. When you have something good in your mind… a story you want to tell, then the animation will have structure and interest involved with it.
