Yeah,Its possible,it runs on the psp fine,it'll run better on the gp2x cuz the gp2x has more ram and that'll be a big advantage over psps 32 mb ram,noting that Openmugen requires large amount of memory.
On another note,Just like xnopasaranx said
OpenMugen
Hi,Im New To GP2X And Forums,Etc. And Searched For Any Mugen Ports For The GP2X,But I Found There Are No Ports,But theres a PSP Port Available,So How Bout Makin A GP2X Port?
PSP Port
EDIT:I mean OpenMugen Not MUGEN.