Dren looks like that for less than half of the movie.
Tip of the hat to the movie as a whole. Splice was not at all what I was led to expect, and I mean that in the best possible way. Rather than being some jump scare-ridden creature flick, the movie was less about Dren and more about the two scientists who create her. Less horror, more science fiction, and a lot of little peeks into the minds of the two main characters. What compels them to create Dren, how her presence in their lives affects their marriage, how they affect her development, etc. Dren is actually a fairly minor character until the last 1/3 or so of the movie. She's just kind of there until she ages and starts looking more human. Adrien Brody and Sarah Polley deliver rock-solid performances.
Wag of the finger to whoever made the decision to turn the last 20 minutes into a by-the-numbers creature flick. It wasn't entirely out of left field, but it still seemed a tad incongruous with the tone and pacing of the rest of the movie. Plus I wasn't thrilled about the seemingly blatant sequel set-up at the end. Coming soon, Splice 2: Revenge of the Rise of the Double Helix.
Big, fat middle finger to the people in charge of marketing. The trailers and ads almost completely misrepresent the movie, the last 20 minutes notwithstanding. I can only imagine how many people may have been convinced to skip it because of the horrendous marketing campaign. If I hadn't read the reviews, I might have missed out myself. I'm sure some who did go experienced disappointment because of the discrepancy between preview and product. I distinctly remember a few people walking out after 30 or so minutes on the day I saw Splice.
If you're in the market for the kind of horror movie the trailers promise, avoid Splice. You probably won't walk away happy. If stripped down science fiction with interesting characters sounds like something you'd like to see, see Splice. I don't care if you rent it, go to a dollar theater, or view it by some other cheap method. Just give Splice a chance.