It was good
I think what really made me laugh was the the delivery of the last line.
I think the delivery, or the acting needs to be improved. Other than, that, I think you did really good. I can see where this could have really worked.
I think voting lower than 5 is way too harsh. For one, as you stated, you're trying to improve, and I definitely respect that. Definitely keep it up. I can see where you can get better.
IDEA - nice little twist there. just needed to be executed better. for an example, time it so the other person doesn't know it's HCL acid, but think of other ways they could react. The eyes of the owner/seller. good. His laugh felt kind of forced, like the guy who was screaming. Once you figure out how to do that, things are solid. I think the best way to do it is make your "soundtrack" first, than animate that, so you could time it better. I'm not sure how you do it, but we've all got different methods. This is a method I've considered with stuff I'm working on. Unfortunately, I have nothing posted Flashwise (yet), so I can't say too much.
HUMOR - it was there, but the last line actually came out well, and that's where i laughed. it's a funny concept, but it just needed to be delivered better.
ART - I think you did great here, even with animating.
Looking forward to more of your works. Hopefully my review was helpful.
Best of everything! :c)