Ask away. If your first question was "Can I plug a USB flopping into a Pi and load games?" The answer is no, USB floppy drives don't support the Arc's sector size. We image the games on an original Archimedes and then usually spend months trying to figure out how to get them to run properly...and that's before trying them on a RiscPC or Pi
The Pi compatibility was started nine months ago, so is in its early stages and still beta. I'm spending every spare minute coding to improve compatibility, very little of it is straight forward, usually it involves trying different things until something works and invariably involves detailed knowledge of the RISCOS source code as lots of low level bits aren't documented.
So, in answer to your second question, "Can I help?" Possibly...
Before a games is released, a lot has to happen:
1. Manuals / boxes have to be scanned
2. Manuals and instructions need converting to PDF
3. Box artwork needs cleaning and assembling into JPG
4. Floppies need to be imaged
5. The game has to be tested in its native state on different hardware from the original A310 up to the Pi
6. The game has to be tested on different RISCOS versions, from 3.1 up to the latest 5.x
7. CPU compatibility has to be checked on ARM 600, 7500, StrongARM and ARM9
8. A boot script (Obey replacement for !Run) has to be coded to fix any compatibility issues. For most games a boot script is required to get them running on the A310, as a lot of the early games either didn't configure the memory to their needs, or did it in such a way as to trash your machine config. Certain developers also loved to use abbreviated commands, which now translate into completely different commands (eg *L. instead of *LOAD, *L. now translates to *LOGON). A few games also require bugs fixing, be it compiler errors or bugs that only became apparent on later hardware.
At this point the games are retested on every platform and OS version and provided we have rights, released on here. You can probably see why so few have been released...it's a lot of work for one man, so help is always welcome.
Due to the amount of coding required for Pi compatibility, I've not touched any of the above for the best part of two years, around 150 games have been scanned / imaged but have yet to be looked at. This hasn't been helped by the fact that when I started this project I wasn't working and two years in stupidly decided to go back to work. I took three months off to code the JIT and and now back working until the end of the year, I'm lucky if I get a few hours of coding in a week.
Coding wise, ADFFS is heavy going so you probably wouldn't want to get involved with that. The outstanding development is fairly technical, such as translating the sound system, adding 26bit module compatibility and WIMP interaction - all fairly complicated.
I'm always after testers as that's the biggest chunk of the time, this is somewhat limited on the Pi at the moment as so few games have been tested, so invariably involves writing a boot script (see !ADFFS.obey). These start life as a copy of the !Run and are then modified to add in compatibility.
Another area that people can help is in locating games we're missing. Physical game donations are more than welcome as are scans and floppy images. The one thing we are not asking for is money, this project is privately funded by myself and is non-profit.