Well, first-person non-shooter, but it's still action-based like Half-life 2 is. It's not a totally different genre like RPG or puzzle game or anything, people will pick it up and say "hey this feels like a FPS", even though it's not based around guns or even projectiles really. I think there's a misconception that if a game is first-person but doesn't feature guns that it must be totally different from regular FPS games, when in fact a game can still have a lot in common with them even without guns. For example one of the most interesting aspects of HL2 is the physics gun, but really that weapon has nothing to do with shooting. Obviously even if you use the physics gun in HL2, you're still going to think that the game feels like an FPS despite the fact that you aren't actually "shooting" anything (well, not in the traditional sense anyway). Though now that I think about it a lot of FPS games have elements that aren't based around shooting at all, for example in Chronicals of Riddick you probably spend as much time using stealth and fighting hand-to-hand as you do shooting, but everyone who's played it will still say that the game is a first-person shooter. Basically with my idea there's more of an emphisis on movement and using physics like inertia and gravity (gotta take advantage of the physics system in HL2!), but it'll still use "FPS-like" controls and a pretty familiar interface.
But yeah, it is a lot harder to make an innovative game based on an FPS than it is to make a totally different kind of game, I think HL2 has definatly taken a step towards innovation and originality with it's physics system (assuming it works out as well as they've shown in videos). A lot of games have tried the "innovation in a FPS" idea before and kinda failed, remember Trespasser? I still think remaking that game in the Source engine would be pretty cool...maybe I'll make that my SECOND project