I was gonna give 4 stars for it being a demo, but I don't think its fair. The combat system alone is just revolutionary for OpenBOR and actually the whole beat em up genre. Just be aware there is not a lot of content and stages yet.
More games need to try combat systems like this. It can be very complicated in the beginning. The many combo routes can be confusing and maybe too much. But within time you will get to know your favorite character better and start remembering and mixing moves like you want on the fly. It gives no much freedom and variety.
I hope it does not get abandoned because we have a possible gem here on the making.