Hooka has released a port of Wolfenstein 3d to the GP2X, heres what he says:
Just thought I'd let you know I did a really crappy port of wolf3d to the gp2x, for the moment it's a little slow, had some issues with the joystick control, no saves and needs alot more work! Consider this a very early beta to try if you really, really want to. It's only the shareware wolf3d version for now and the data files go in the same directory as the .gpe
Download Here --> http://gp2x-emulation.dcemu.co.uk/gp2xwolf3d.shtml