The cassette loading method is going to limit this to games that fit entirely in RAM and never access their disk once loaded. That's going to rule out a lot of games. Obviously anything that needs more than one floppy, but even a lot of games that do fit on one side are still going to want to access the disk they came on.
Would it not be possible to load a disk-writer program into ram, which prompts you to insert a blank disk, and then proceeds to buffer and write subsequent audio data onto the disk, such as a disk image?
Although, no Ultima / Ultima II in the game list :(
That was the first game I played on the Apple...
(The Bards Tale would be another great one...)