What do you think, nekoniaow and jotd666, could 1MB Chipram solve this slowdown-problem in Galaga500? One of my four Amiga500 was modded back then in the 90's and has a switcher, with which I can switch between "512kb Chipram + 512kb Slowram" and "1MB Chipram and 0kb Slowram". 1MB Chipram was great in tools like Protracker back then, because it allowed song-modules, to be much larger and there are also a few games, that only works correctly with 1MB Chipram. But mainly, you benefited from it, in a few tools.
I have not tried Galaga500 on exactly this A500 so far, because it's in my old room, in my parents house. Must try it out, how the game runs there, in the next week. Nevertheless, if it runs faster there, this is also not the ultimate solution then, because the vast majority of A500 users, will surely not have modded their computer in this respect, but it's definitely interesting to try it out.