Just tried Boffin on the GP2X. It's using a very strange screen resolution. It's wider than 320 pixels - which is the widest screen size I catered for in the video emulation!
If you move Boffin right a bit, then move left and jump, he appears on the screen. Don't know how playable that is...
Edit: Link to download updated to version 0.6-1
http://beebem-unix.bbcmicro.com/downloads/beebem06-1.tar.gz
After many many delays, a new version of BeebEm for the GP2X is finally here!
New features:
* Better video emulation.
* Improved user interface.
Enjoy!