Naturally, the steathily-added features set off a storm of speculation amongst the fan community. Just how far is Valve going with these World of Warcraft-esque changes? When can I buy an epic mount for my Heavy?

In reality, the hats will be purely cosmetic in nature--at least initially. Valve's Robin Walker told us that while the TF2 team is interested in exploring more radical, RPG-style mechanics, the plan is to slowly introduce these new elements in order to "measure the effect of each change, both on the game and on the community."

"The primary change here is simply the decoupling of achievements and unlockables, which is the source of most of the negative feedback we've received around previous class packs," said Walker. "It'll provide multiple ways for players to get items, with a plan to add more over time."

Read on for our full interview with Walker, who answers several of our heady questions--including when to expect the new items, and where TF2 might be headed next.

Shack: Are the head-slot items being added before the Sniper update?

Robin Walker: The plan is for the head-slot items to be out before the Sniper pack is out, but if we don't get them done in time they'll just be bundled into the pack.

Shack: How will these items work on a basic level? Will they randomly drop from players that people kill?

Robin Walker: We're going to try a few different things, but the first ones won't manifest themselves inside the game itself, because it'd allow servers to cheat the system.

Shack: Will these items carry bonuses that impact gameplay?

Robin Walker: Right now they're all cosmetic only, but it's obviously more interesting if they become more than that, so we're still thinking about that. Shipping them without gameplay changes seems like a good way to tackle the first problem, which is to ensure we don't break our silhouette based class identification. It also starts us on another path that we're interested in, which is allowing players to have some control over their appearance.

Shack: So would you say that you're still considering whether to add extra items/weapons that impact the game beyond cosmetic variation?

Robin Walker: We plan to do more than just cosmetic items, but we like to go one step at a time to be able to measure the effect of each change, both on the game and on the community.

Shack: Any plans for consumable items? And will these items be tied to each class, or carried over to all of your classes?

Robin Walker: The short answer is: possibly. Part of the reason we want to do this kind of design work in TF2 is because it's a product in which players send us a ton of great feedback. This means we'll quickly find out if we're screwing up, which is an amazingly useful thing when we want to try new things.

Shack: Should we expect to see more item slots--chest, feet, elbows--added in the future?

Robin Walker: See the "possibly" answer above.

Shack: Will players be able to trade these items?

Robin Walker: This is a good example of the kind of decision we'll be listening to the players around. If it's something they all want to do, then yep, you can expect us to do it.

Shack: Some users are concerned that you can permanently delete hard-won items from your backpack. Should they be? How is that system intended to work?

Robin Walker: Not really. We put in some strong wording in the update to discourage them from doing it for now, but as soon as the next update ships they'll be able to find any item, including ones they've deleted in the past. The reason we shipped it in the last update, even though there was no real reason at all to use it, was to get some real world testing. So thanks to the 270 people who went ahead and deleted items! In addition, it gave our support team some warmup practice in handling the inevitable customer issues resulting from this kind of system.

Shack: Will the backpack/head items be part of a separate game mode, or is this going to be patched into TF2 proper?

Robin Walker: It'll be in TF2 proper. The primary change here is simply the decoupling of achievements and unlockables, which is the source of most of the negative feedback we've received around previous class packs. The head-slot items are all cosmetic at this point, so they haven't resulted in any significant balance issues in any of our existing game modes.

Shack: Are there plans for any kind of "vanilla" game mode to filter out the new items for players that just want to play a quick match of the core game?

Robin Walker: Almost all the requests we've received in this area have come from competitive players. While we don't think this update adds any new issues for competitive play, we are aware of the desire for leagues to control what their players are using, so we're thinking about how we can help them do that. Still, we're optimistic as ever. We believe that the more interesting & viable choices available to competitive players, the more depth there is for them to use to their advantage. It'd be a shame if they're prevented from exploring the strategic possibilities that the new items add.

Shack: Plenty of players love the achievements/unlockables, but the "grind" has intimidated others who thought of TF2 as a "pick-up-and-play" experience. Do you sympathize with the latter group?

Robin Walker: The feedback from these kinds of players, in addition to a variety of other players, has been one of the drivers behind this update. It'll provide multiple ways for players to get items, with a plan to add more over time. Some players want to use their skill to succeed, others want to be more casual. Our goal is to ensure that they all get to have some fun finding items and making some choices about which ones fit their playing style.

Shack: On an unrelated note, are the "Meet the" videos finished, or should we expect the rest?

Robin Walker: Nope, we're not done yet. There's still the Pyro, Medic, and Spy to go. We've saved the best for last!

Shack: Can you talk about the TF2 comics at all? Are those going to be entirely web-based? Free? Story-driven or short strips?

Robin Walker: We're not ready to talk about them yet, sorry.

Shack: Thanks Robin.