Emu64 XL 4+

Th edev added semi-support for D64's - I say "semi" because it's ridiculously clunky and unlike any other 64 emulator. You have to go to an external website, upload your D64 file, copy a chunk of encoded text, paste it back in the app, and then it'll load the D64. I tested it with Ultima V, which I wanted to play - and it... worked... ish. Changing disks is an exercise in futulity. Ultima V finally did load but it look several minutes to load, and then several minutes to get past the first welcome screen, and then the actual intro screen was so slow I gave up as the game would have been completely unplayable. And I don't get why - there's other C64 emulators foir the iPad before that work perfectly fine, and don't have these crazy limitations - just not in the app store. Oh well. I'm glad the dev is trying, I suppose.

It is a good attempt but without external joystick (PS4 gamepad) or being able to redefine keyboard (magic keyboard) for joystick emulation, it just doesn't work well.

The keyboard appears only at the top of the screen and can't be moved to the bottom of closed. When running the fractal program from the included demo disk, it runs so slowly. It's amazing that this emulator for a 40 year old computer doesn't have an option to run the processor at the speed of a modern one. Finally, there emulator died in the middle of the fractal demo due to some audio error. The demo didn't even use audio. Aside from that demo, the emulator overall is awkward and clumsy. Using an actual Commodore 64 from the 1980s would be a much better experience.