First of all, the sound design is really fantastic! Awesome job!
You really carefully designed around most of the issues that fpsc has, really good job. What you didn't handle so good is the combat itself. It feels good in the first level where enemies always come from the front, but once they can attack from different sides (second level), things start to feel very fpsc-ish again. I think you could handle this with more linear level design, as the open areas you provide are not truly open at all, anyway.
And as all models are just slightly retextured default models that come with the engine, here is quite some space for improvement, too.
But really good job on this one! It is good *for an fpsc engine game*