Just tried out the demo, and I enjoyed it a lot! I liked the character's design, the animation quality was very good, and the bosses were enjoyable. I enjoyed how the game is easy to understand, though I also hope it gets harder in the 3rd stage and onward.
There are only a few issues I ran into (which might only be in the demo). First, enemies in some rooms can hit you quickly upon entering the room, and the knockback causes you to transition back to the other room. This mostly occurs in the 2nd area nearer to the boss room. Second, I don't think the second boss can finish you off so long as you aren't within a certain distance. This makes the boss a lot less threatening. If he could do something such as swinging a chain to grab you, that would solve his reach issue. And lastly, the defeat animations are too good to only play once. Having the event continue and/or including a gallery would be very convenient.
Overall, definitely an impressive game, especially for such a small team! Great work! I'll be sure to check out the full version later as a treat to myself!