Although none of these games have been released yet, it's a fair bet they'll be competing against each other for customers in the coming months.
Going head to head against Halo on the same iron-- Microsoft's upcoming Xbox video game console, will be Unreal Championship, announced today by Infogrames. UC will be an Xbox exclusive, and is slated to be released next spring. Infogrames obviously has a lot of faith in the title, as you can tell from their release:
Unreal Championship will be the definitive action game for Microsoft's new video game system, said Laddie Ervin, director of marketing at Infogrames, Inc.'s Los Angeles label. The console market is ready for a leader in this genre on next generation systems and Unreal Championship is poised to take that spot.
But then again, that's what PR flacks are for, right?
On the other end of the spectrum, running on PCs, is Planetside from Verant/Sony, a massively multiplayer first person shooter. While debates rage on about the relative quality of Planetside's and Halo's eye candy, not to mention Verant's reputation for less than stellar customer service, there are still some Halo fans who see in Planetside's design doc what they were hoping for from Halo as it was originally announced.
Planetside is also showing at E3, and the Planetside site at Station.com has screenshots from what they are showing there.