I'll admit I dragged my feet on playing this one, because I've never been a fan of "performance" games like Rock Band, and the thought of having to talk out loud and look like a fool was intimidating me. But I finally found time to play late at night with no one around and... it was good!
The game had no problem picking up my voice, and I was able to beat it with no problem, despite the fact that I spoke fairly quietly the whole time. I enjoyed the concept of a middle-aged man becoming a magical girl. The scenario in general was entertaining, even if there wasn't much story. If I can pick up and enjoy this game, I'd say you done quite well, as I think there'd be a big market for people who enjoy this sort of thing way more than me!
There's one elephant in the room that I've tip-toed around so far and that's the art. While it's fairly cohesive... I'm not a fan of AI art. This probably doesn't bother everyone, but it's a big turn off for me. I am glad you declared it up front though, I appreciate that. It's not as big a deal to me in a jam game, but if you were to make a full-length game out of this I'd like to see all the art made by the artist, not just the original concepts.
Otherwise, I think this is a really cool concept that's well executed and has a lot of potential. Nice work!