I played it on Linux with Proton 7, works pretty well. Only issue is that the blank viewport appears over the title screen so you can’t see the game title itself. I didn’t notice any issues in-game.
The mechanics were simple enough but I was thrown off by the control scheme of having X as shoot and Square as sprint. I remember MGS having Square as the shooting button and that’s what I was instinctively trying to do so I would prefer to swap them.
The portraits and demon sprites need another pass to tie them in better but otherwise you’ve nailed the art style, I love it.
This is really good, very interested to see where you can go with this.