There's a Nathan Bitner Interview on Halonews.com talking with the Producer and Creative Developer on Halo, Bungie Software's upcoming third-person single-player and multiplayer action game. Thanks opiate. Here is a bit that talks about the single-player portion of the game that addresses possible comparisons to TRIBES:

Creating a really finely tuned single-player game is more of a challenge than multiplayer, where you don't have to worry so much about AI, balancing difficulty with different player skill levels, relating a compelling story, etc. As popular as multiplayer is, there are still many more people who play single player, so in that respect, Halo is practically guaranteed a larger audience than competing titles.

I have to add that Halo is not just “Bungie’s answer to Tribes”, as many people have commented. Halo is going to bring aspects of both multiplayer and solo gaming to the table that no other game has ever seen before. It is fair to say that both the Sierra series and Halo are going to focus on teamplay when it comes to the multiplayer environment. However, just a few of the things that will distinguish the game (and, believe me, there are many others that I can’t yet talk about) are:...