You probably just need a different emulator. The game uses opcodes which not every emulator implements.
I see the glitches as well. Since this was made with NESFab, I think you could just compile the compiler with `make ISA=legal` and then recompile the game to make a version that will work on everyone's emulator.
The game looks really cool! I was able to play it better with a controller than with a keyboard in the browser, but the flickering was hard to see through.