Hello, this info was super helpful. It actually led me to find that the game doesnt run properly at anything but 60fps. So I recommend sticking to that (the way I implemented it was wrong and didn't actually increase performance anyway from my recent testing). As for your specs; yeah theyre pretty old. From 2017, ontop of being integrated graphics youre not getting much out of it in the way of gaming. That being said, while im always trying to find and implement ways to improve performance. I don't think I can guarantee a perfectly optimized experience for a system that old. The game has to use higher resolution assets for its hand drawn boss animations. And optimizing those is way harder than a pixel art game with way lower resolution assets.
Sorry for the bad news, hopefully I discover a way to make it work better for lower end systems. But your reply was extremely useful, so thank you!