Woogal has done the incredible and ported Duke Nukem 3D to the GP32, heres what he says:
What doesn't work yet? -
Saving and loading (although config file will save if you exit).
SFX
Music
How fast is it? -
Seems full speed to me . Tested by running a version on linux and seeing roughly how long it takes to run from one place to another. Seemed to be the same time on both linux and the gp32. I was getting serious slow down when the game first started for a while, but on the last couple of test runs that had mysteriously gone. If it does slow down then try waiting a while as I think it may be to do with refilling the image cache.
Download Here --> http://gp32emu.dcemu.co.uk/dukenukem3d.shtml