A beer too much Don't take this the wrong way but...
...There's nothing wrong with being inspired, but I don't really understand the point of doing a 'cover' of someone else's flash. This place already seems to be flooded with enough crappy 'parodies' and 'tributes'.
To be honest I think your animation itself is fine, everything wrong with this flash stems from the fact it isn't original, as a result you unfortunately didn't really capture any of the original humour either, you just came across as an ACTUAL serial killer.
I'd have to agree though with an earlier comment that although the storyline was basically nicked, this actually had no similarity to the other valentines cartoon(in style/sound etc.)
You seem to have enough animation skill + style to create something original and actually. Personally I'd much rather see a crap original than a crap cover.