I've checked all those videos on youtube, and that small one on screwattack, and I've also played the demo.
Well, all I can say is that I really enjoyed it a lot. The tension was very high while playing, especially against the boss. It was really exciting, a lot of fun, and the musics fit well with that. It felt like playing something similar to Mega Man in a lot of aspects, except faster.
So yeah, I really liked it a lot.
I was thinking of buying it, but then I read here that eventually there will be a rom avalaible so yeah, now I'll have to think about it...
One thing that bothers me though is how some sounds are "borrowed" from other games. For example, the sound of the menu popping up (1:47 on the small video at screwattack http://screwattack.com/videos/Quick-Look-At-Battle-Kid-Fortress-Of-Peril
) is from Shadow Of The Ninja (aka Blue Shadow aka Kage), and some other sounds seem to directly come from the Mega Man games.
I also think the look of the character is a double-edged sword. Sure it's helping to make the game famous (considering the success of IWBTG), but on the other hand it forces people to make a comparaison with IWBTG, and make it look like "just IWBTG for the NES" (I heard some people say that). It's a real shame because Battle Kid has its own personality, spirit, and the gameplay has very little to do with IWBTG when you start to look into it. It makes Battle Kid seem to be in the shadow of IWBTG while it could have stood on its own.
But anyway like I said, those are more like nitpicks, overall I REALLY enjoyed the demo a lot and I'm considering buying it (had you not told about the rom I would have probably ordered it already). Keep up the good work, it feels good to see some other NES fanatics.