Man, i love this game! It kinda feels like the NES version of Nioh. I don't know if you have ever played the original Ninja Gaiden Triology on NES but this game also reminds me of Ninja Gaiden especially in terms of gameplay. Like the enemies pop out of nowhere all of a sudden :) The boss fight is so Ninja Gaiden like. Btw you need to add a boss music and a health bar for the boss fight.
The art of the game is very good. I love the character, enemy and boss designs. The flame throwing lantern enemies were annoying but i like that every enemy has a week point. Oh man the kabuto crab samurai boss fight, i totally dig it's design. You even made a second phase for the boss i guess. After you damage it for a certain times, it starts a second attack, spraying water or something like that.
Gameplay mechanics. The high attack, low attack mechanic is a good touch, it adds some depth to combat. You need to do the right attack according to enemy's stance. I tried to the same thing in my game but i think your implementation is much better. In the current state of the game blocking is not very useful. I beat the whole game without blocking even once but i'm guessing that you will want to improve the combat mechanics further in the future so that it'll become more vital. Dropping the lantern into tall grass is a very nice touch. The fire spreads through the grass and burns down enemies. Cool delivery of enviromental weapon. I think it should give more damage to the enemies though and we don't get damage when we walk in the burning grass, there should be a risk/reward aspect to it. I think health replenishment should be handled in a different way, it makes the game a little easy. You can something like power ups. Checkpoints are good too but some people may like more challenge. You may conside placing less frequent checkpoints maybe in the final version of the game.
That's all i have to say right now. I'm gonna follow your itch.io account bcs i really like your style. Your team did a great job and i wish you make successful games in the future. Best of luck to you!