If it's because of a technical reason I get it, but for me the immersion's pretty broken from not being able to strap a girl who's just been sequestered away wearing the Halo to a machine to have her brain properly drained. As much fun as it is to blow away those first few levels, it really bites into the evil villain feeling when you can't let your evil empire handle the first few stages. I'd truly recommend allowing it to at least be usable after level 1!