Kind of neat. I think I would have liked more enemies/reasons to switch dimensions. As it was, I could just stick within the shooting dimension comfortably.
Surprisingly challenging. Graphics and sound minimal but functional. Music isn't too bad. Didn't buy the "connected worlds" theme at all. Some innovation, but essentially boils down to a shooter. You get a 3 overall because the core gameplay, while simple, is pretty good.
Get's boring really fast, it needs some more elements.