I felt really conflicted about this game at first. On one hand, to say that it was "inspired" by Gyossait is a bit of an understatement. The visual style was cut whole-cloth from that game, and several sprites in the game look almost exactly the same (the Executioner gunmen and the same gun-wielding men in Gyossait, the crawling spiders and the mutated spider creatures in Gyossait, the font of the Tanas' dialogue, the conceit of having his dialogue written on the background as a means of conveying, acid pits, the pushable weight/platform object, the stills/cutscenes, the layout and animation of the opening, et multiple cetera). It can't be argued that this game is HEAVILY cribbing from Gyossait in the artwork. Frankly, I think it warrants a splash page at the beginning (or end) of the game thanking Amon26 for the inspiration and directing people to his page so they can see the source.
...but at the same time, I can't say this is a ripoff of Gyossait, because it has a lot of elements that made the game its own. There was much more mid-game choice (obey/rebel) and that increased player agency, which is always a good thing. I felt less railroaded in this game than I did in parts of Gyossait. And of course, I played it through multiple times, so it was obviously good enough and engaging enough to keep me drawn in.
So yeah, I like it. If you're going to steal, steal from the best, as they say. And you took some of the best elements from Gyossait's visuals and used them to paint a new picture. It's good. Inspiration is a good thing, and imitating good artists is a good thing too. All I'd really say is give the artists that inspire you a very conspicuous shout-out, just out of respect. Who knows who might be inspired by you in the future? I'm sure you'd like the credit as well.