Updated the thread for Tuesday 19th.

The first Heavy unlockable is something completely unique. It's the Sandvich. The best description is from the site:

The Sandvich is the Heavy's first unlockable. It tastes as good as it looks and heals 120 health. Like in real life, the decision to eat a Sandvich must not be taken lightly; The Heavy is completely vulnerable during the four second eating process, and his loud, happy sounds of vigorous chewing will draw enemies like tiny ant cowards to a picnic. OF DEATH. On the bright side, the Heavy's Sandvich supply is unlimited, so his only real concern is being caught short while enjoying this delicious edible device. The Sandvich is a great tool for a Heavy defending an area, as it gives him the ability to replenish health between enemy waves without having to abandon his post. Similarly, an offensive Heavy without a Medic can step back from the front line and grab a quick snack before resuming his rampage. Beware, however: the Heavy must set aside his shotgun to take the Sandvich, and enemy Snipers are much more dangerous for a Heavy wielding only a minigun.

The best thing about todays update is the new Meet the Team video which is a must watch - Meet the Sandvich

I've updated the thread for Monday 18th. A completely new mode has been revealed - Arena Mode. The best description is from the link: Arena features smaller maps that play out in shorter periods of time. The round ends once one team has no players left in the arena, or when the central capture point has unlocked and been captured. Rounds tend to be very fast and highly competitive, with an emphasis on your team's ****makeup and your plan to counter the opposing team's ****choices. Arena mode is great for smaller matches of three vs. three players, while still comfortably supporting huge knockdown twelve-on-twelve brawls.

Also two new Area maps have been created:

Lumberyard has an unbalanced structure, with one half of the map climbing up towards a large mountain peak, while the other dips down into a valley. A series of rooftops at the map's center serves as the key battleground area, with lateral flanking being the key maneuver at ground level. When the capture point becomes active after 60 seconds, multiple entrances open up into the central control point, which becomes the focus of the fighting as the match nears its end. Lumberyard is one of the few Arena maps without water, and contains only a single health kit. The kit sits on a log above a deadly pit, making it a great ambush spot for Pyros, Demomen, and Soldiers to send unwary enemies to their deaths.

In contrast to Lumberyard, Ravine has a far more open ground level with emphasis on control of four key choke points. A series of canals in Ravine's lower level provide an excellent opportunity for stealth kills and flanking maneuvers. Like all arena maps, the capture point in the middle becomes active after 60 seconds.

Click the link for more details.