This is such a great game. The base mechanics feel smooth, though I do have a few notes.
First of all, a funny one: I didn't know what the assassins ability did at first, so I looked it up. But when you look up "Shogun Showdown Assassin" it's just a bunch of videos of the shogun showdown level of Hitman Silent Assassin, so you might have some issues there with the relation.
Secondly, later in the game the final enemies attack way too fast. While the health feels fine, having enemies on both sides ready to attack within two turns of spawning requires some REALLY specific contrivances to get through with skill, and at that point it's kind of already significantly luck based. I will admit, roguelikes are known for their RNG, and I have gotten better at some of the early attacks.
Thirdly, keep the first boss the same. It feels like an amazing first hurdle for players, and fighting him every run significantly increased my understanding of how the games mechanics worked considering knowing them allows you to no-hit him, and to no-hit him you need to know them well. It's really fun.
Fourthly, I kind of feel like the kid telling the teacher that they forgot to collect homework, so I'm just gonna put it out there that there are a few glitches that can be abused to do more than you're supposed to be allowed to.
Anyways, keep going with this please! It's very fantastic, and I can't wait for updates!