I liked this a lot. The art wasn't top notch, but you made up for it in a lot of ways. I've seen the siren (or mermaid, thanks to the fouth POTC) thing done before, but you took it in your own direction and got a fairly unique and creepy little story out of it. I was actually a bit surprised by the action scenes. I didn't expect them to turn out that well after watching evil siren lady take two inch steps in the very beginning. At that rate, it should have taken her several days to get to the door XD The action was pretty solid overall, but you do need to work on the slower parts.
You did nice work synching it with the music, although I have to pick at the sound overall. There issue I have is that there are parts of the flash that are completely silent and I was waiting for something to fill the gap. The oil spill especially was a bit weird. It was like watching a silent movie, and I was worried the music wasn't coming back. Silence can heighten drama, but it was just too long at that point. I strongly recommend finding a way to fill the void, but I'd say try to get the music back in rather than throwing in a dozen different sound effects.