They actually got an experienced professional (http://www.imdb.com/name/nm0935313/) to do the voice of the villain, but she doesn't show up at all until over halfway through the game. Which is another big problem with the game.
I would venture that the other VAs don't have very good experience.
Brianna Wu (who I'm learning more and more actually didn't really do that much of the game development despite all the credit she gets!) says that they couldn't afford to hire a lighting person. Which is really silly, as all they needed to do to add lighting in an Unreal Engine game is define lights in the scene. Maybe what this means is that they couldn't spend any time designing materials for objects, but even using a simple diffuse-only material for everything would look a lot better than this.
She has blamed a lot of the design limitations on a lack of RAM on iPhone 4S:
http://steamcommunity.com/workshop/filedetails/discussion/386454385/606068060820082878/
I'm not a game developer, but I'm experienced enough with programming and how 3D games work to know that a lot of her claims are really limitations of her team and not the device. What it shows is that there's very poor dynamic management of resources. For example, voice acting should not put pressure on RAM, especially on a device which is guaranteed to have storage with fast seek times. This also explains why the load times are pretty bad.
