Are any of you gamers?

I started watching Defiance and I was interested to see (well before the show was out) that they were planning to integrate the TV show with an online game. So, after the show came out, I wandered over to see what the game was about. But I am not a gamer, so I am completely perplexed.

Here is the link to the game, so people can answer my clueless queries.

While it asks you to sign up and get an online profile etc., it looks like the game is a game for XBox360, PC or Playstation 3. It talks about how it updates and you play against others etc. So how does that work? Am I understanding it correctly when I assume that it's a game that you're playing on your gaming system (and could play just on your system), but you can use your internet to play a larger game?

Has anyone played it? I doubt my PCs would run it that well and I don't have the other gaming systems mentioned, so I'm a bit bummed I won't get to see what it's about. I was hoping it was completely online and maybe even free (advertisement sponsored). I guess, like I say, I'm well out of the loop on these things.

Maybe I should get a gaming system for actual games rather than just fitness things one of these days. I just don't think I'd have time to play it.