Well, that was interesting.
I'm not judging the story, because it's personally not my cup of tea (luckily you balanced out the sappy romance story with some sort of humor- this was pretty funny overall.) But for what it was, it wasn't bad. For one I'm impressed by all the water effects. I've never seen that kind of thing implemented in flash, or at least properly. That was a nice touch. But your animations for the characters themselves, well, in short they're lazy. If you must tween everything (which looks awkward because at times the characters' shoulders dislocate), at least add some easing to them. Movements seemed a little robotic, and lipsyncing also seemed a bit unnatural.
But it seems your goal was to create a story, not necessarily a masterpiece of animation. You've succeeded in that, at the very least.
Voice acting, well, everyone did a fairly good job, however the last guy who spoke- his voice was very quiet, and hard to understand. Should've turned that up a tad bit louder.
Keep it up, but try to polish the way your characters move a bit. Also try to refrain from reusing animations. Overall, not bad, but could be better.