Just a guess, but you'd probably need to mix FPSE with FPSECE (for Windows CE). Taking the GPU part from FPSECE would be alot easier, as it uses GAPI, which is basically writing directly to the framebuffer. The ARM optimisations would be very usefull too, as the first release with no ARM opt. wasn't playable on anything but a 624MHz PXA-270 X-Scale PPC (The PXA-270 clocked at 312MHz out performs a PXA-255 at 400MHz). I'm guessing that the UI stuff from FPSE would be easier to port than the Windows CE UI though.