Starting with just two new items for the Medic, Valve are going to be gradually rolling out new, unlockable weapons for every class. These will be alternative versions of their current loadouts that, once unlocked by earning a certain number of achievements, you can pick and choose from on a new 'Loadout' menu.

The unlockables aren't just beefed up versions of the weapons, they balance major advantages and disadvantages to fundamentally alter the role of that class. The first Medic unlock, for example, is called the Overhealer. Instead of temporarily buffing people's health to 50% above their normal maximum, it permanently boosts them to double their standard health. The downside is that it'll be dramatically worse at building Ubercharge - in fact, Valve are toying with not letting it Uber at all.

No details on what the second unlock they'll be rolling out in this update will be, beyond the basics: it'll be another Medic healing ray, and it'll change the way the class plays all over again. The first is earned by acquiring half of the thirty-five new Medic achievements, the second for acquiring them all.