The Games
So it can play movies on the move. "What else?" I hear you ask. Well, those nice people at GamePark strongly encourage the homebrew scene, and have released an official set of libraries for Visual C++ to allow people to write their own apps. Once your GP32 is registered at GamePark HQ, the Freelauncher app allows you to play anything from an enormous set of homebrew titles. Of particular note are Doom, SCUMMvm and the rather large selection of emulators.
Doom is an accurate representation of the classic game, and is compatible with all four commercial Doom WAD files (plus the shareware version of DOOM.WAD). The version available for download is a little dated and lacks features such as saving or sound - the owner of GBAx.com has offered to take over development once he gets ahold of the source, which is good for all concerned. Unlike the GBA version of Doom, this is full-screen & in the original Doom resolution, and completely free of slowdown.
SCUMMvm is a cross-platform program which is able to play games based on versions 3-7 of the Lucasarts SCUMM engine, as seen in games such as Monkey Island, Sam & Max, and Day of the Tentacle. The GP32 version is a little buggy in places, but supports full sound & saving on all games except Monkey Island 1. This will be fixed once development picks up again (the former developer broke his GP32, which didn't help matters).
The emulators are a mixed bag, but all hold hope for the future. The NES and Game Boy are currently emulated at 100% speed, as is the PC Engine. However, as most emulators are simply ports of PC emulators, they start to struggle on more complex systems. There is a SNES9X port available, but it's pretty slow. In the works are 100% new & optimised Megadrive & Game Boy Advance emulators - although the respective authors have not made any public releases for download. The prospect of playing GBA games on the same unit that can watch episodes of South Park is a good one indeed...