HPC Doom 0.92
the author of this app says:
This is a full-featured Doom port for CE2.11/HPC2000 Handheld PC's, including the J680, 690 and 720. It has full PC appearence and functionality. You can play with any IWAD, including shareware, Doom, Ultimate Doom, Doom2, Plutonia and Tnt. It also features full sound support.