My God what a game!!!! Easily my favorite indie title form itch.io ever. The graphics, the music, I loved them!! I read that you want to make a similar game, so I will make a few suggestions as to what to avoid for your next title. Please, do forgive me if I'm a little harsh. I'm a fan and I'd like to see you improve your art even further.
- First of all, the controls. I really like the core loop here. Block / parry, and then slash. That's cool and all and I think you can use that for your next game as well, but not without a few adjustments. The controls need to be a lot more responsive, and I think you should add a few more extra moves for when we keep pressing the LMB. I understand that this is a stealth game, but the boss battles are not. Though I really liked them too, I sometimes found myself wishing that I could slash them more just for a better sense of satisfaction.
- Level design was OK in my opinion, with a few moments of absolute brilliance. For example, the introduction of the boss was incredible, when he shot one of our enemies. And the path to the second boss is a really nice little puzzle (though I never would have figured it out on my own!!) So maybe work on more complex / interesting levels. The level design is good as it is, but I think you have what it takes to make each one really count.
- You could delve on the story a little bit more. I know that exploring a story in an indie game is such a pain in the ass and adds a f**k ton of working hours, but I think you could keep the story fairly abstract but make it have more of an impact on the player. Environmental storytelling is a really easy and effect version of doing that. For example, we can find out more about who Gregory is, why he's a vigilante and who were the bosses etc.
Anyway, looks like I already talked too much haha. I loved the game and will be waiting for more!