Most of the available Windows CE devices are Pocket PC’s and therefore most of the available Windows CE software is written for Pocket PC’s. The main difference of Windows CE Pocket PC’s and Handheld PC’s is the used GUI (Graphical User Interface).
Because of the GUI differences there exist also differences in the available system DLL’s. The main reason of the software incompatibility are the lack of some Pocket PC specific DLL’s in the Handheld PC OS. Almost all Pocket PC applications uses the aygshell.dll and almost all game, emulator and video applications uses the Game API DLL gx.dll.
If your desired Pocket PC application doesn’t run on your Handheld PC, you can verify with the tool "Executability Check" which DLL’s and functions are missing on your Handheld PC. Copy these missing DLL’s into the Windows or applications directory.