The lads at Violent Gamer did a nice summary of the game and I'm also linking the developer videos, so I'll be brief: It's first person, player-vs-player medieval war where your play-style is determined by the weapon you choose to use. Plain and simple. My favorite quote from the developer is that if you choose to use close-range melee weapons you will have to get in there and "go berserker on people's faces". Nice. They also note that 'objective taking' will be more than raising a flag. You are a medieval army and will behave as such, damnit, so set about to the slaughter of those villagers immediately!
Here is the kickstarter video:
It's not an MMO, so once you buy it there are no more fees. Also very nice. Here is an earlier You Tube video they have done as well. I recomend you check this one out if you like, say, Mount and Blade, or are looking for something different in your FPS 'shooter' games. Plus they're Canadian so you know they will be nice guys ;)