I am actually really enjoying this. The splatter along the head of the creature seems to be okay though it clearly doesn't have enough contrasts in shape and size of splatters though I think lighting could also be addressed to improve the overall idea for the splatters in general. Look at the original and see the splatters as they are change in light over his abdomen, that could be attempted with your splatters subtly, maybe.
The other part I think that is limiting this is the use of the same splatter along the top and bottom of the alien...it is the same and the fact that one section is hard to see due to the over darkened section doesn't help matters.
I really like this idea and would love to see whatever else you do to it.