Painful introduction.
A lot of flash artists make the mistake of using title-like introduction credits (no background) make the flash look professional. I think most would agree that it looks somewhat lazy, and is used to replace real content. Don't release something until you have something worth watching.
Get more sprites, get more backgrounds.. It's already there for you, it doesn't take much work to compile it all if you're just going for a run-of-the-mill sprite flash.