After reading some glowing reviews here (which, unfortunately, always triggers my suspicious and cynical nature), I was willing to give this movie a chance, though I was a bit worried that, from the title, I might be in for a cheesefest or someone trying way too hard. Luckily, neither is the case.
There are some distracting things wrong with this movie, but what's surprising is the sheer number of things that are RIGHT. If you're a fan of grindhouse movies, you're probably pretty forgiving of cheap-looking special effects, watery fake blood, and poorly developed characters. In fact, one could make a pretty good argument that a true grindhouse movie almost requires these elements.
This is an impressive debut, and I'd like to see what comes in the future. It'd be a shame if the Soska sisters never got any attention and a chance to prove that they can make really good movies. In the future, however, I'd probably suggest bringing in a script doctor to tighten up the script and give the characters a little more... well, character. Also, less singing in the next movie, please. Whenever someone gets up on a stage and sings, I immediately think to myself, "Filler!" It was admittedly a decent method of contrasting the characters, but that doesn't mean it wasn't also a bit tedious to sit through. I'd give this movie an 8/10, if they cut the musical numbers out.