While the game itself isn’t free-to-play (boo), there is a limited (but not too limited) free version of it (yay).
So just how limited is it? Well, as it turns out, it’s significantly more full-featured than a demo (which is probably why they haven’t referred to it as a demo).
You get the full game, minus a few maps, and miss out character customization, custom content, and the server browser. To compensate for that last one, you can still use Toxikk’s matchmaking.
The developers, Reakktor Studios (can’t fault them for being consistent in their naming schemes), supplied a nifty table for everyone to get a good idea what to expect from the free version of the game.