I love single screen arcade games like this and bubble bobble. In fact, besides run and gun, they are probably my second favourite type of game.
This looks and sounds GREAT and controls beautifully. However, as a gaming veteran I have to be honest about the stuff I don't agree with. I quit the game after about 20 minutes as there were just no weapon power ups and I genuinely got bored. I am not upset I bought it as I am glad to support an indie dev and always WILL support indie devs, but I would hope you'd appreciate my honest opinion rather than be dishonest. It IS fun, don't get me wrong, and the music is so appropriate, and I think the mechanic of starting weapon less and having to get the knife first in each level was a really clever take I haven't seen before, as it adds to the skill required.
HOWEVER - where are the speed ups, or sword power ups for say more range, or different weapon pickups? For me it's a big deal to lack that stuff and just be the same over and over again, but that's of course just my opinion.
Cheers