Sierra, Valve, and Sega have formally announced that they are working with Gearbox Software (the developers of the Half-Life mission pack Opposing Force) and Captivation Digital Labs to port Half-Life to the Sega Dreamcast. This new port will feature a brand new single player mission featuring Barney, everyone's favorite multiplicious security guard. Here's an excerpt from the full press release, with some more details:

In development by Northern California-based Captivation Digital Laboratories in conjunction with Gearbox Software and Valve, Half-Life: Dreamcast is set to be even more extraordinary than the original PC version. The Sega Dreamcast edition will feature several optimizations, including higher polygon player characters, dramatic lighting and special effects, to showcase the power of the Sega Dreamcast and deliver a fresh and exciting player experience for console gamers.

Half-Life: Dreamcast will also feature an all-new single player mission that surrounds the Black Mesa Security Guard character, Barney. This special mission is being custom created for the Dreamcast by Gearbox Software, the Texas-based development team that created Half-Life: Opposing Force(tm), the official PC expansion for Half-Life and runner-up to 1999 Game of the Year by PC Gamer magazine (March 2000).