You can't play 3-D mode without having 3-D glasses (you actually can but the graphics look horrible). No multiplayer option.
Based largely on Sega's arcade smash hit "Space Harrier", Worldrunner was one of the first any only true 3-D games for the NES, complete with those goofy-looking red & blue 3-D glasses. Fortunately for the rest of us, there's also a non-3-D option as well. The plot's rather simple-as Worldrunner, a little guy who can jump incredibly high, you run through several worlds taking on a dragon/snake-like boss at the end of each, collecting hearts & stars along the way to power your energy & weapons.
The 2-D graphics are good enough by themselves, but a bit more color would be nice despite some nice backgrounds. The game doesn't slow down any during battles either, and moves at a good pace. A nice, and funny little touch is when you pause the game, your character sits down and starts breathing heavily like he's tired! The sounds & music are about in the middle: Solid and acceptable yet not spectacular or really bad.
Controls are simple and easy to learn, although learning how to do the jumping properly takes practice. When you're flying around battling bosses, controlling yourself is easy and the repsonse is good. The gameplay also includes some hidden mini-games along the way and it's nice when it switches from running to flying for the boss battles. It's only a 1 player game, though.
If you like games like Space Harrier but don't have a Sega system, this game should keep you happy for a while. And I wouldn't bother playing in 3-D. Even with the glasses it's nothing spectacular and you'll likely just wind up with a bad headache.