It's actually pretty good. At first I wasn't too convinced because it begins with a series of long empty corridors, and when finally enemies are introduced, they're pretty easy and we see only one type for a little too long. Yeah, they're bats.
But the physics are pretty fun. Punch a bat and you will send it satisfyingly far. Then you earn upgrades to punch yourself off walls for a boost, and become a "bowling ball" breaking through some walls.
I'm left wanting more. Although the game isn't perfect. Some epic boss battles would have been nice, but the bosses are, sadly, just arenas in which you fight half a dozen creatures.
Still, it IS worth checking out. And I like that unlike so many homebrew NES games, this one wasn't designed to punish players. The difficulty is just right.
I just got that emulator a few days ago along with one for TG-16. I'll play it Monday. From the video it looks well designed and fun. I've checked out a good amount of Xbox Live's Indie platformers in the last few months and I have to say at first glance this looks better than 90% of them.