If people are looking for worthwhile Jaguar games, I can name plenty of them. I've had a Jaguar since 1995 or so, and am gradually working towards a complete set of games for it (as well as the JagCD).
The Jaguar really does have more power than people give it credit for. Many of the early companies really didn't tap the system very well, and just ended up porting 16-bit games like Dragon: The Bruce Lee Story, NBA Jam, and Double Dragon V, which obviously show none of the capabilities of the system. If you really want to see what the system can do, check out these games:
Battlesphere - This game was under development for about 5 or 6 years, and didn't end up coming out until Atari had basically ceased to exist. Because of this, the game is very hard to find (I still don't have a copy myself). However, it's generally considered to be one of the best games on the system. It's a space shooter with 3D graphical effects and gourad shading and all that kinda stuff.
Battlemorph - This is a completely different game from the one above. This is the CD-based sequel to Cybermorph (The Starfox ripoff that was packed with the Jaguar). The game has much better sound, better graphics (higher framerate and texture mapping), and basically just much more variety in the gameplay, adding things like going underwater and through tunnels and such. This is probably my favorite game on the system.
Alien vs. Predator - This one was probably the most sought-after title for the system back in the days, but honestly, it hasn't aged too well. The 3D engine AVP is based on is really no better than Wolfenstein, and can't do many of the effects that Doom does, like windows and elevators and ledges and such. However, the game has a great sense of atmosphere that you rarely see in video games. It's tons of fun to play late at night with the lights off.
Doom - The Jaguar port of Doom was excellent back in the days, and beat out just about all the other versions... unfortunately, it still lacks a lot of the features of the PC version, such as in-game music, lighting effects, and a few other things. Also, some of the level geometry has changed a bit. Since Doom is all open source now, I'm sure we'll see much better ways of playing Doom on the GP2X.
Wolfenstein 3D - I still think the Jaguar has the best version of Wolf3D ever, even beating out the PC version. The graphics are completely overhauled with higher resolution wall textures and character graphics, you get two new weapons (the flame thrower and the rocket launcher), and the framerate is great. Rumor has it that they ported this game over a weekend just as a test before they did Doom, and it turned out so well that they decided to soup it up and release it.
Power Drive Rally - An overhead view rally racing game. The graphics are all 2D, but the game is a lot of fun. The cars control well, the graphics are colorful, and everything scrolls very smoothly. Excellent game overall.
Attack of the Mutant Penguins - Another colorful 2D game that's a lot of fun. Again, no crazy 3D effects here, but the game is very unique. The storyline is that aliens are invading, and (due to a mishap) they've disquised themselves as penguins. Your job is to kill the alien penguins while saving the REAL penguins. This generally involves building traps and such.
Atari Karts - A ripoff of Super Mario Kart. The game has great graphics and is very smooth, but was obviously rushed to market. There is no battle mode, and the selection of powerups in the game is rather weak. It's still a fun game, but honestly, the real Mario Kart is much better.
Iron Soldier - You pilot a giant mech and wreak havoc in cities in order to complete your missions. It's surprisingly satisfying to swat away helicopters and smash huge buildings into bits with your fists! The game seems a little slow paced by todays standards, but this was a big hit for the Jaguar at the time. There's also a sequel available on cart and CD... although I haven't played it, it seems to be more of the same.
Raiden - Well, it's Raiden, the classic arcade shooter. It's basically arcade perfect (minus the vertical screen) and is probably the best home version of the game available, even beating out the Playstation version. Although if we're talking about the GP2X here, I'd go for MAME instead.
Tempest 2000 - Everyone already knows this game is great, so I guess I don't really have to say anything else about it here.
Rayman - This excellent, colorful side-scrolling platform game actually started off on the Jaguar before being ported to a bunch of other systems. Easily the best platform game on the system.
Defender 2000 - This game doesn't seem to get a lot of attention, and although it's not as good as Tempest 2000, I still think it's tons of fun. There are actually 3 versions of Defender here; the original Defender, Defender Plus (Mostly the same as the original with new stuff added in), and Defender 2000 itself, which expands things quite a bit. It has a great techno soundtrack, but the game can be very frustrating at times as you fly around so fast that you'll often hit stuff without realizing it.
Missile Command 3D - Like the "2000" games, this actually has three different versions of Missile Command... the original, a graphically improved one with 3D graphics and a scrolling view of the sky, and a completely different 3D mode where your three missile bases are in a triangular formation around the city... this mode has you taking a first-person perspective from the bases themselves and firing lasers at the incoming missiles. The game also has some truly amazing boss fights in it. Unfortunately, the game is rather short with only a handful of levels in it.
Super Burnout - Basically just a ripoff of Hang-On, but a very good one.
Pinball Fantasies - This used to be the best video pinball around, and is still a lot of fun... although games like Time Shock and the other Pro Pinball games have made it seem a little old fashioned.
Highlander: Last of the McCleods - For some reason, they based this game on the less popular cartoon version of Highlander rather than the movies... The gameplay is basically Resident Evil with a sword, with a lot of cutscenes taken straight from the animated series. Polygon count on the characters is pretty low, but the pre-rendered backgrounds are nice.
Hover Strike - This game was originally going to be Battlezone 2000, but for whatever reason, they decided to give you a hovercraft instead of a tank. Everything is texture mapped, and dynamic lighting abounds... unfortunately, the framerate is pretty poor (back then it didn't seem so bad), and the controls are a little funny (remember, it's a hovercraft... so you slide around a lot). There's a CD version of this game too that has a few new levels, better music, and some graphical improvements.
There are quite a few other games that are worth trying too, like Evolution Dino Dudes (a Lemmings type of game) and Flashback.... but make sure to stay away from games like Checkered Flag, Club Drive and Trevor McFur, as they're pretty bad. Even though I have a Jaguar, I'd love to be able to play these games on the GP2X... I'm doubtful that the GP2X has the power to emulate it 100%, but it would still be cool.
--Zero